diff --git a/src/com/blankj/concurrent/BoundedQueue.java b/src/com/blankj/concurrent/BoundedQueue.java
new file mode 100644
index 00000000..7ee65b05
--- /dev/null
+++ b/src/com/blankj/concurrent/BoundedQueue.java
@@ -0,0 +1,69 @@
+package com.blankj.concurrent;
+import java.util.LinkedList;
+import java.util.concurrent.locks.Condition;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/9/22
+ */
+public class BoundedQueue {
+
+    private LinkedList<Object> buffer;    //生产者容器
+    private int maxSize ;           //容器最大值是多少
+    private Lock lock;
+    private Condition fullCondition;
+    private Condition notFullCondition;
+    BoundedQueue(int maxSize){
+        this.maxSize = maxSize;
+        buffer = new LinkedList<Object>();
+        lock = new ReentrantLock();
+        fullCondition = lock.newCondition();
+        notFullCondition = lock.newCondition();
+    }
+
+    /**
+     * 生产者
+     * @param obj
+     * @throws InterruptedException
+     */
+    public void put(Object obj) throws InterruptedException {
+        lock.lock();    //获取锁
+        try {
+            while (maxSize == buffer.size()){
+                System.out.println("满了，添加的线程进入等待状态");
+                notFullCondition.await();       //满了，添加的线程进入等待状态
+            }
+            buffer.add(obj);
+            fullCondition.signal(); //通知
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * 消费者
+     * @return
+     * @throws InterruptedException
+     */
+    public Object get() throws InterruptedException {
+        Object obj;
+        lock.lock();
+        try {
+            while (buffer.size() == 0){ //队列中没有数据了 线程进入等待状态
+                System.out.println("队列中没有数据了 线程进入等待状态");
+                fullCondition.await();
+            }
+            obj = buffer.poll();
+            notFullCondition.signal(); //通知
+        } finally {
+            lock.unlock();
+        }
+        return obj;
+    }
+}
diff --git a/src/com/blankj/concurrent/BoundedQueueTest.java b/src/com/blankj/concurrent/BoundedQueueTest.java
new file mode 100644
index 00000000..a66939f0
--- /dev/null
+++ b/src/com/blankj/concurrent/BoundedQueueTest.java
@@ -0,0 +1,38 @@
+package com.blankj.concurrent;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/9/22
+ */
+public class BoundedQueueTest {
+    public static void main(String[] args) {
+        BoundedQueue boundedQueue = new BoundedQueue(5);
+
+        ExecutorService executorService = Executors.newFixedThreadPool(2);
+        executorService.execute(()->{
+            for (int i=0;i<10000;i++){
+                try {
+                    boundedQueue.put(new Object());
+                } catch (InterruptedException e) {
+                    e.printStackTrace();
+                }
+            }
+        });
+        executorService.execute(()->{
+            for (int i=0;i<10000;i++){
+                try {
+                    boundedQueue.get();
+                } catch (InterruptedException e) {
+                    e.printStackTrace();
+                }
+            }
+        });
+    }
+}
diff --git a/src/com/blankj/concurrent/ConditionUseCase.java b/src/com/blankj/concurrent/ConditionUseCase.java
new file mode 100644
index 00000000..9994ff19
--- /dev/null
+++ b/src/com/blankj/concurrent/ConditionUseCase.java
@@ -0,0 +1,66 @@
+package com.blankj.concurrent;
+
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.locks.Condition;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/9/22
+ */
+public class ConditionUseCase {
+
+    public Lock lock = new ReentrantLock();
+    public Condition condition = lock.newCondition();
+
+    public static void main(String[] args)  {
+        ConditionUseCase useCase = new ConditionUseCase();
+        ExecutorService executorService = Executors.newFixedThreadPool (2);
+        executorService.execute(new Runnable() {
+            @Override
+            public void run() {
+                useCase.conditionWait();
+            }
+        });
+        executorService.execute(new Runnable() {
+            @Override
+            public void run() {
+                useCase.conditionSignal();
+            }
+        });
+    }
+
+    public void conditionWait()  {
+        lock.lock();
+        try {
+            System.out.println(Thread.currentThread().getName() + "拿到锁了");
+            System.out.println(Thread.currentThread().getName() + "等待信号");
+            condition.await();
+            System.out.println(Thread.currentThread().getName() + "拿到信号");
+        }catch (Exception e){
+
+        }finally {
+            lock.unlock();
+        }
+    }
+    public void conditionSignal() {
+        lock.lock();
+        try {
+            Thread.sleep(5000);
+            System.out.println(Thread.currentThread().getName() + "拿到锁了");
+            condition.signal();
+            System.out.println(Thread.currentThread().getName() + "发出信号");
+        }catch (Exception e){
+
+        }finally {
+            lock.unlock();
+        }
+    }
+
+}
diff --git a/src/com/blankj/easy/_053/Kuai_shou_test.java b/src/com/blankj/easy/_053/Kuai_shou_test.java
new file mode 100644
index 00000000..84e82356
--- /dev/null
+++ b/src/com/blankj/easy/_053/Kuai_shou_test.java
@@ -0,0 +1,25 @@
+package com.blankj.easy._053;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/4/3
+ */
+public class Kuai_shou_test {
+    public static void main(String[] args) {
+        String a = "abc";
+        for (int i=0;i<a.length();i++){
+            System.out.println(a.charAt(i));
+            System.out.println((int)a.charAt(i));
+        }
+        System.out.println(Integer.MAX_VALUE);
+    }
+
+    public int count(int[][] a,int x,int y){
+
+        return 1;
+    }
+}
diff --git a/src/com/blankj/easy/_053/Solution.java b/src/com/blankj/easy/_053/Solution.java
index 9e343c79..0bc79aa3 100644
--- a/src/com/blankj/easy/_053/Solution.java
+++ b/src/com/blankj/easy/_053/Solution.java
@@ -45,4 +45,15 @@ public static void main(String[] args) {
         int[] nums0 = new int[]{-2, 1, -3, 4, -1, 2, 1, -5, 4};
         System.out.println(solution.maxSubArray(nums0));
     }
+
+    public int maxSubArrayByD(int[] nums) {
+        int len = nums.length, dp = nums[0], max = dp;
+        for (int i = 1; i < len; ++i) {
+            dp = nums[i] + (dp > 0 ? dp : 0);
+            if (dp > max) {
+                max = dp;
+            }
+        }
+        return max;
+    }
 }
diff --git a/src/com/blankj/myself/AddTwoNumbers.java b/src/com/blankj/myself/AddTwoNumbers.java
new file mode 100644
index 00000000..7bbe47f2
--- /dev/null
+++ b/src/com/blankj/myself/AddTwoNumbers.java
@@ -0,0 +1,47 @@
+package com.blankj.myself;
+
+import com.blankj.myself.HasCycle_fast_slow_point.ListNode;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/10/3
+ */
+public class AddTwoNumbers {
+
+    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
+        ListNode res = new ListNode(0);
+        ListNode curr = res;
+        int x,y,unit,carry=0;
+        while (l1!=null||l2!=null){
+            x = (l1==null?0:l1.val);
+            y = (l2==null?0:l2.val);
+
+
+            unit = (x + y + carry)%10 ;
+
+            curr.next = new ListNode(unit);
+            carry = (x + y + carry)/10;
+
+            if(l1!=null){
+                l1=l1.next;
+            }
+
+            if(l2!=null){
+                l2=l2.next;
+            }
+
+            curr = curr.next;
+
+        }
+
+        if(carry!=0){
+            curr.next = new ListNode(carry);
+        }
+
+        return res.next;
+    }
+}
diff --git a/src/com/blankj/myself/ArrHeaderTailMax.java b/src/com/blankj/myself/ArrHeaderTailMax.java
new file mode 100644
index 00000000..b08fee10
--- /dev/null
+++ b/src/com/blankj/myself/ArrHeaderTailMax.java
@@ -0,0 +1,95 @@
+package com.blankj.myself;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/9/28
+ */
+public class ArrHeaderTailMax {
+
+    public static int max(int[] a){
+        int sum = 0;
+        for(int i=0;i<a.length;i++){
+            sum = sum + a[i];
+        }
+        System.out.println("sum="+sum);
+
+        //return maxDetail(a,sum,0,a.length-1,0);
+
+        return maxDetail(a,0,a.length-1,0);
+
+    }
+
+    //public  static int maxDetail(int[] a,int sum,int leftIndex,int rightIndex,int max){
+    //    if(rightIndex-leftIndex>1){
+    //        int leftMax = sum - maxDetail(a,sum-a[leftIndex],leftIndex+1,rightIndex,max);
+    //        int rightMax = sum - maxDetail(a,sum-a[rightIndex],leftIndex,rightIndex-1,max);
+    //
+    //        max = max + Math.max(leftMax,rightMax);
+    //        System.out.println("leftMax="+leftMax+",   rightMax="+rightMax+",   Math.max(leftMax,rightMax)="+Math.max(leftMax,rightMax));
+    //        System.out.println("max = " + max);
+    //        return  max;
+    //    }else {
+    //        System.out.println("leftMax="+a[leftIndex]+",   rightMax="+a[rightIndex]+",   Math.max(leftMax,rightMax)====  "+Math.max(a[leftIndex],a[rightIndex]));
+    //        return Math.max(a[leftIndex],a[rightIndex]);
+    //    }
+    //}
+
+    public  static int maxDetail(int[] a,int leftIndex,int rightIndex,int max){
+        if(rightIndex-leftIndex>1){
+            int chooseNum = maxDetail(a,leftIndex+1,rightIndex,max)>maxDetail(a,leftIndex,rightIndex-1,max)?
+                a[rightIndex]:a[leftIndex];
+            max = max + chooseNum;
+            return  max;
+        }else {
+            return Math.max(a[leftIndex],a[rightIndex]);
+        }
+    }
+
+    public static void main(String[] args) {
+        //int v[] = { 1, 2, 3, 6, 9, 5, 7, 4, 2, 6, 9, 5, 8, 7, 2, 1, 55, 3, 6, 9, 7, 5, 2 };
+        int v[] = { 10, 70,3,2,8,900};
+
+        int n = max(v);
+        System.out.println(n);
+
+        //System.out.println(max2_dync(v));
+    }
+
+    /**
+     *
+     *
+     * dp[i][j]=sum[i,j]-min(dp[i-1][j],dp[i][j-1])
+     * @param b
+     * @return
+     */
+    public static int max2_dync(int[] b){
+        int n = b.length;
+        int[] a=new int[n+1];
+        int[][] dp=new int[n+1][n+1];
+        int[] sum=new int[n+1];
+        for(int i=1;i<=n;i++){
+            a[i]=b[i-1];
+            sum[i]=sum[i-1]+a[i];
+            dp[i][i]=a[i];
+        }
+
+        for(int i=n;i>0;i--){
+            for(int j=i+1;j<=n;j++){
+                dp[i][j]=sum[j]-sum[i-1]-Math.min(dp[i+1][j],dp[i][j-1]);
+            }
+        }
+        int first=dp[1][n];
+        int second=sum[n]-first;
+        System.out.println(first+" "+second);
+        return first;
+
+    }
+
+
+
+
+}
diff --git a/src/com/blankj/myself/ClimbStairs.java b/src/com/blankj/myself/ClimbStairs.java
new file mode 100644
index 00000000..be00b65b
--- /dev/null
+++ b/src/com/blankj/myself/ClimbStairs.java
@@ -0,0 +1,67 @@
+package com.blankj.myself;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/9/23
+ */
+public class ClimbStairs {
+    public static void main(String[] args) {
+        ClimbStairs climbStairs = new ClimbStairs();
+        System.out.println(System.currentTimeMillis());
+        System.out.println(climbStairs.climbStairs(46));
+        System.out.println(System.currentTimeMillis());
+
+        System.out.println("--------------------------");
+
+        System.out.println(System.currentTimeMillis());
+        System.out.println(climbStairs.climbStairs2(46));
+        System.out.println(System.currentTimeMillis());
+
+        System.out.println("--------------------------");
+        System.out.println(System.currentTimeMillis());
+        System.out.println(climbStairs.climbStairs3(46));
+        System.out.println(System.currentTimeMillis());
+    }
+    public int climbStairs(int n) {
+        if(n==1){
+            return 1;
+        }
+        if(n==2){
+            return 2;
+        }
+        return climbStairs(n-1)+climbStairs(n-2);
+    }
+
+    public int climbStairs3(int n) {
+        int[] nums = new int[n];
+        nums[0]=1;
+        nums[1]=2;
+        if(n==1){
+            return 1;
+        }
+        if(n==2){
+            return 2;
+        }
+        for (int i=2;i<n;i++){
+            nums[i]=nums[i-1]+nums[i-2];
+        }
+        return nums[n-1];
+    }
+
+    public int climbStairs2(int n) {
+        if(n==1){
+            return 1;
+        }
+        int[] nums = new int[n];
+        nums[0] = 1;
+        nums[1] = 2;
+        for (int i=2;i<n;i++){
+            nums[i] = nums[i-2] + nums[i-1];
+        }
+        return nums[n-1];
+    }
+}
diff --git a/src/com/blankj/myself/CountAndSay.java b/src/com/blankj/myself/CountAndSay.java
new file mode 100644
index 00000000..d29c4682
--- /dev/null
+++ b/src/com/blankj/myself/CountAndSay.java
@@ -0,0 +1,30 @@
+package com.blankj.myself;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/10/3
+ */
+public class CountAndSay {
+    public String countAndSay(int n) {
+        StringBuilder res = new StringBuilder("1");
+        for(int i=1;i<=n;i++){
+            char[] tempArr = res.toString().toCharArray();
+            char temp;
+            int k=0;
+            res = new StringBuilder();
+            for (int j=0;j<tempArr.length;j++){
+                if(tempArr[j]==tempArr[j+1]){
+                    k = k+1;
+                }else {
+                    res.append(k).append(tempArr[j]);
+                    k = 0;
+                }
+            }
+        }
+        return res.toString();
+    }
+}
diff --git a/src/com/blankj/myself/Exercise14.java b/src/com/blankj/myself/Exercise14.java
new file mode 100644
index 00000000..ef1e453d
--- /dev/null
+++ b/src/com/blankj/myself/Exercise14.java
@@ -0,0 +1,40 @@
+package com.blankj.myself;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/9/28
+ */
+public class Exercise14 {
+    static int max(int[] a, int i, int j) {
+        int sum = 0;
+        while (i <= j) {
+            sum += a[i];
+            i++;
+        }
+        return act(a, sum, 0, a.length - 1);
+    }
+
+    private static int act(int[] a, int sum, int l, int r) {
+        int lmax, rmax;
+        if (r - l > 1) {
+            // 意思是先选一个，然后求剩下数组对方先选获得的最大值，用sum减去对方获得的最大值，即是自己的最大值
+            // 然后比较选头还是尾更好
+            lmax = sum - act(a, sum - a[l], l + 1, r);
+            rmax = sum - act(a, sum - a[r], l, r - 1);
+            return lmax > rmax ? lmax : rmax;
+        } else {//剩下2个
+            return a[l] > a[r] ? a[l] : a[r];
+        }
+
+    }
+
+    public static void main(String[] args) {
+        int v[] = {1, 2, 3, 6, 9, 5, 7, 4, 2, 6, 9, 5, 8, 7, 2, 1, 55, 3, 6, 9, 7, 5, 2};
+        int n = max(v, 0, v.length - 1);
+        System.out.println(n);
+    }
+}
diff --git a/src/com/blankj/myself/GetIntersectionNode_two_linklist.java b/src/com/blankj/myself/GetIntersectionNode_two_linklist.java
new file mode 100644
index 00000000..c2371376
--- /dev/null
+++ b/src/com/blankj/myself/GetIntersectionNode_two_linklist.java
@@ -0,0 +1,23 @@
+package com.blankj.myself;
+
+import com.blankj.myself.HasCycle_fast_slow_point.ListNode;
+
+/**
+ * Description:leecode 160. 相交链表
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/10/2
+ */
+public class GetIntersectionNode_two_linklist {
+    public ListNode getIntersectionNode(ListNode headA, ListNode headB) {
+        ListNode pA = headA;
+        ListNode pB = headB;
+        while (pA!=pB){
+            pA = pA==null?headB:pA.next;
+            pB = pB==null?headA:pB.next;
+        }
+        return pA;
+    }
+}
diff --git a/src/com/blankj/myself/GetKthFromEnd.java b/src/com/blankj/myself/GetKthFromEnd.java
new file mode 100644
index 00000000..f5723fce
--- /dev/null
+++ b/src/com/blankj/myself/GetKthFromEnd.java
@@ -0,0 +1,67 @@
+package com.blankj.myself;
+
+import com.blankj.myself.HasCycle_fast_slow_point.ListNode;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/10/3
+ */
+public class GetKthFromEnd {
+    public static void main(String[] args) {
+        ListNode head = new ListNode(1);
+        ListNode tail = null;
+
+        //head.next=new ListNode(2);
+        //head.next.next=new ListNode(3);
+        //head.next.next.next=new ListNode(4);
+        //head.next.next.next.next=new ListNode(5);
+
+        for (int i=1;i<5;i++){
+            if(tail==null){
+                tail = new ListNode(i+1);
+                head.next = tail;
+            }else {
+                tail.next = new ListNode(i+1);
+                tail = tail.next;
+            }
+
+        }
+
+        GetKthFromEnd getKthFromEnd = new GetKthFromEnd();
+        getKthFromEnd.getKthFromEnd(head,2);
+
+
+    }
+
+    public ListNode getKthFromEnd(ListNode head, int k) {
+        int size = 0;
+        ListNode headSecond = head;
+        while(head!=null){
+            head = head.next;
+            size = size + 1;
+        }
+        ListNode res = null;
+        ListNode temp = null;
+        int index = 0;
+        while(headSecond!=null){
+
+            index = index + 1;
+            if(size-k<index){
+                if(res==null){
+                    temp = new ListNode(headSecond.val);
+                    res = temp;
+                }else{
+                    temp.next = headSecond;
+                    temp=temp.next;
+                }
+            }
+            headSecond = headSecond.next;
+        }
+        return res;
+    }
+
+}
diff --git a/src/com/blankj/myself/HammingWeight.java b/src/com/blankj/myself/HammingWeight.java
new file mode 100644
index 00000000..70be6598
--- /dev/null
+++ b/src/com/blankj/myself/HammingWeight.java
@@ -0,0 +1,23 @@
+package com.blankj.myself;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/10/2
+ */
+public class HammingWeight {
+
+    public int hammingWeight(int n) {
+        int res = 0;
+        while(n != 0) {
+            res += n & 1;
+            n >>>= 1;
+        }
+        return res;
+
+
+    }
+}
diff --git a/src/com/blankj/myself/HasCycle_fast_slow_point.java b/src/com/blankj/myself/HasCycle_fast_slow_point.java
new file mode 100644
index 00000000..de831b30
--- /dev/null
+++ b/src/com/blankj/myself/HasCycle_fast_slow_point.java
@@ -0,0 +1,42 @@
+package com.blankj.myself;
+
+import java.util.HashSet;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/10/2
+ */
+public class HasCycle_fast_slow_point {
+
+    public boolean hasCycle(ListNode head) {
+        if(head==null||head.next==null){
+            return false;
+        }
+        ListNode fast = head;
+        ListNode slow = head;
+        while (fast!=null&&fast.next!=null){
+
+            fast = fast.next.next;
+            slow = slow.next;
+
+            if(fast == slow){
+                return true;
+            }
+
+        }
+        return false;
+    }
+
+    static class ListNode {
+      int val;
+      ListNode next;
+      public ListNode(int x) {
+          val = x;
+          next = null;
+      }
+    }
+}
diff --git a/src/com/blankj/myself/HasCycle_hash.java b/src/com/blankj/myself/HasCycle_hash.java
new file mode 100644
index 00000000..75ba70ba
--- /dev/null
+++ b/src/com/blankj/myself/HasCycle_hash.java
@@ -0,0 +1,36 @@
+package com.blankj.myself;
+
+import java.util.HashSet;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/10/2
+ */
+public class HasCycle_hash {
+
+    public boolean hasCycle(ListNode head) {
+        HashSet<ListNode> hashSet = new HashSet<>();
+        while (head!=null){
+            if(hashSet.contains(head)){
+                return true;
+            }else {
+                hashSet.add(head);
+                head = head.next;
+            }
+        }
+        return false;
+    }
+
+    class ListNode {
+      int val;
+      ListNode next;
+      ListNode(int x) {
+          val = x;
+          next = null;
+      }
+    }
+}
diff --git a/src/com/blankj/myself/InorderTraversal.java b/src/com/blankj/myself/InorderTraversal.java
new file mode 100644
index 00000000..e1326a56
--- /dev/null
+++ b/src/com/blankj/myself/InorderTraversal.java
@@ -0,0 +1,43 @@
+package com.blankj.myself;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/9/14
+ */
+public class InorderTraversal {
+    public static void main(String[] args) {
+
+    }
+
+
+    public List<Integer> inorderTraversal(TreeNode root) {
+        List<Integer> list = new ArrayList<>();
+        dfs(root,list);
+        return list;
+    }
+
+    public void dfs(TreeNode root,List<Integer> list) {
+        if(root==null){
+            return;
+        }
+        dfs(root.left,list);
+        list.add(root.val);
+        dfs(root.right,list);
+    }
+
+
+
+    public class TreeNode {
+      int val;
+      TreeNode left;
+      TreeNode right;
+      TreeNode(int x) { val = x; }
+    }
+}
diff --git a/src/com/blankj/myself/InorderTraversalByStack.java b/src/com/blankj/myself/InorderTraversalByStack.java
new file mode 100644
index 00000000..e94eaa73
--- /dev/null
+++ b/src/com/blankj/myself/InorderTraversalByStack.java
@@ -0,0 +1,35 @@
+package com.blankj.myself;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Stack;
+
+import com.blankj.myself.InorderTraversal.TreeNode;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/9/14
+ */
+public class InorderTraversalByStack {
+
+    public List<Integer> inorderTraversal(TreeNode root) {
+        List<Integer> list = new ArrayList<>();
+        Stack stack = new Stack();
+        TreeNode curr = root;
+        while (curr!=null||!stack.isEmpty()){
+            if(curr!=null){
+                stack.push(curr.left);
+                curr = curr.left;
+            }else {
+                curr = (TreeNode) stack.pop();
+                list.add(curr.val);
+                curr = curr.right;
+            }
+        }
+        return list;
+    }
+}
diff --git a/src/com/blankj/myself/IsPalindrome.java b/src/com/blankj/myself/IsPalindrome.java
new file mode 100644
index 00000000..56a60f71
--- /dev/null
+++ b/src/com/blankj/myself/IsPalindrome.java
@@ -0,0 +1,27 @@
+package com.blankj.myself;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/9/21
+ */
+public class IsPalindrome {
+    public static void main(String[] args) {
+        IsPalindrome isPalindrome = new IsPalindrome();
+        System.out.println(isPalindrome.isPalindrome(1001));
+    }
+    public boolean isPalindrome(int x) {
+        boolean isPalindrome = true;
+        String xStr = String.valueOf(x);
+
+        for (int i=0;i<xStr.length()/2;i++){
+            if(xStr.charAt(i)!=xStr.charAt(xStr.length()-i-1)){
+                isPalindrome = false;
+            }
+        }
+        return isPalindrome;
+    }
+}
diff --git a/src/com/blankj/myself/KthLargest.java b/src/com/blankj/myself/KthLargest.java
new file mode 100644
index 00000000..773fd378
--- /dev/null
+++ b/src/com/blankj/myself/KthLargest.java
@@ -0,0 +1,34 @@
+package com.blankj.myself;
+
+import com.blankj.myself.InorderTraversal.TreeNode;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/10/2
+ */
+public class KthLargest {
+
+    int resp;
+    int index;
+    public int kthLargest(TreeNode root, int k) {
+        index = k;
+         dfs(root);
+         return resp;
+    }
+
+    public void dfs(TreeNode root){
+        if(root==null){
+            return ;
+        }
+        dfs(root.right);
+
+        if(--index==0){
+            resp = root.val;
+        }
+        dfs(root.left);
+    }
+}
diff --git a/src/com/blankj/myself/LongestCommonPrefix.java b/src/com/blankj/myself/LongestCommonPrefix.java
new file mode 100644
index 00000000..1c3b960a
--- /dev/null
+++ b/src/com/blankj/myself/LongestCommonPrefix.java
@@ -0,0 +1,36 @@
+package com.blankj.myself;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/9/22
+ */
+public class LongestCommonPrefix {
+
+    public String longestCommonPrefix(String[] strs) {
+        String result = new String();
+        String first = strs[0];
+        if(first==null){
+            return "";
+        }
+        for(int j=0;j<first.length();j++){
+            boolean end = false;
+            char b = first.charAt(j);
+            for(int i=1;i<strs.length;i++){
+                String a = strs[i];
+                if(first.charAt(i)!=b){
+                    end = true;
+                    break;
+                }
+            }
+            result = result+b;
+            if(end==true){
+                break;
+            }
+        }
+        return result;
+    }
+}
diff --git a/src/com/blankj/myself/MaxSubArray.java b/src/com/blankj/myself/MaxSubArray.java
new file mode 100644
index 00000000..346eb4e1
--- /dev/null
+++ b/src/com/blankj/myself/MaxSubArray.java
@@ -0,0 +1,21 @@
+package com.blankj.myself;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/10/3
+ */
+public class MaxSubArray {
+
+    public int maxSubArray(int[] nums) {
+        int res = nums[0];
+        for(int i=1;i<nums.length;i++){
+            nums[i] = Math.max(nums[i-1],0) + nums[i];
+            res = Math.max(res,nums[i]);
+        }
+        return res;
+    }
+}
diff --git a/src/com/blankj/myself/MergeTwoLists.java b/src/com/blankj/myself/MergeTwoLists.java
new file mode 100644
index 00000000..cafa81da
--- /dev/null
+++ b/src/com/blankj/myself/MergeTwoLists.java
@@ -0,0 +1,36 @@
+package com.blankj.myself;
+
+import com.blankj.myself.HasCycle_fast_slow_point.ListNode;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/10/3
+ */
+public class MergeTwoLists {
+
+    public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
+        if(l1==null&&l2==null){
+            return l2;
+        }
+        if(l1==null&&l2!=null){
+            return l2;
+        }
+        if(l2==null&&l1!=null){
+            return l1;
+        }
+        ListNode res ;
+        if(l1.val<=l2.val){
+            res = new ListNode(l1.val);
+            res.next = mergeTwoLists(l1.next,l2);
+        }else {
+            res = new ListNode(l2.val);
+            res.next = mergeTwoLists(l1,l2.next);
+        }
+        return res;
+
+    }
+}
diff --git a/src/com/blankj/myself/PredictTheWinner.java b/src/com/blankj/myself/PredictTheWinner.java
new file mode 100644
index 00000000..77938141
--- /dev/null
+++ b/src/com/blankj/myself/PredictTheWinner.java
@@ -0,0 +1,35 @@
+package com.blankj.myself;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/10/1
+ */
+public class PredictTheWinner {
+    public static void main(String[] args) {
+        int v[] = { 1, 2, 3, 6, 9, 5, 7, 4, 2, 6, 9, 5, 8, 7, 2, 1, 55, 3, 6, 9, 7, 5, 2 };
+        PredictTheWinner predictTheWinner = new PredictTheWinner();
+        System.out.println(predictTheWinner.PredictTheWinner(v));
+    }
+
+    public boolean PredictTheWinner(int[] nums) {
+        if(nums.length%2==0){
+            return true;
+        }
+        return predictTheWinnerReal(nums,0,nums.length-1)>=0;
+    }
+
+    public int predictTheWinnerReal(int[] nums,int l,int r){
+        if(l==r){
+            return nums[l];
+        }
+        int left = nums[l] - predictTheWinnerReal(nums,l+1,r);
+        int right = nums[r] - predictTheWinnerReal(nums,l,r-1);
+
+        return Math.max(left,right);
+    }
+
+}
diff --git a/src/com/blankj/myself/PredictTheWinner_Dp.java b/src/com/blankj/myself/PredictTheWinner_Dp.java
new file mode 100644
index 00000000..7ef6370e
--- /dev/null
+++ b/src/com/blankj/myself/PredictTheWinner_Dp.java
@@ -0,0 +1,37 @@
+package com.blankj.myself;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/10/1
+ */
+public class PredictTheWinner_Dp {
+    public static void main(String[] args) {
+        int v[] = { 1, 2, 3, 6, 9, 5, 7, 4, 2, 6, 9, 5, 8, 7, 2, 1, 55, 3, 6, 9, 7, 5, 2 };
+        PredictTheWinner_Dp predictTheWinner = new PredictTheWinner_Dp();
+        System.out.println(predictTheWinner.PredictTheWinner(v));
+    }
+
+    public boolean PredictTheWinner(int[] nums) {
+        if(nums.length%2==0){
+            return true;
+        }
+
+        int[][] dp = new int[nums.length][nums.length];
+        for(int i=0;i<nums.length;i++){
+            dp[i][i] = nums[i];
+        }
+
+        for(int i=nums.length-2;i>=0;i--){
+            for (int j=i+1;j<nums.length;j++){
+                dp[i][j] = Math.max(nums[i]-dp[i+1][j],nums[j]-dp[i][j-1]);
+            }
+        }
+        return dp[0][nums.length-1]>=0;
+    }
+
+
+}
diff --git a/src/com/blankj/myself/RebuildTree.java b/src/com/blankj/myself/RebuildTree.java
new file mode 100644
index 00000000..385d477e
--- /dev/null
+++ b/src/com/blankj/myself/RebuildTree.java
@@ -0,0 +1,45 @@
+package com.blankj.myself;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/9/16
+ */
+public class RebuildTree {
+    
+
+    public TreeNode buildTree(int[] preorder, int[] inorder) {
+       Map indexMap = new HashMap<Integer,Integer>();
+        for (int i = 0; i < preorder.length; i++) {
+            indexMap.put(inorder[i],i);
+        }
+        return reBuildTree(0,0,inorder.length-1,preorder,inorder,indexMap);
+    }
+
+
+    public TreeNode reBuildTree(int preRootIndex, int inorderLeftIndex,int inorderRightIndex,int[] preorder, int[] inorder,Map indexMap) {
+        if(inorderLeftIndex>=inorderRightIndex){
+            return null;
+        }
+        int index = (int)indexMap.get(preorder[preRootIndex]);
+        TreeNode treeNode = new TreeNode(preorder[preRootIndex]);
+        treeNode.left = reBuildTree(preRootIndex+1,inorderLeftIndex,index-1,preorder,inorder,indexMap);
+        treeNode.right = reBuildTree(preRootIndex+index-inorderLeftIndex+1,index+1,inorderRightIndex,preorder,inorder,indexMap);
+        return treeNode;
+    }
+
+
+
+    public class TreeNode {
+      int val;
+      TreeNode left;
+      TreeNode right;
+      TreeNode(int x) { val = x; }
+  }
+}
diff --git a/src/com/blankj/myself/ReverseList.java b/src/com/blankj/myself/ReverseList.java
new file mode 100644
index 00000000..552ee4bf
--- /dev/null
+++ b/src/com/blankj/myself/ReverseList.java
@@ -0,0 +1,30 @@
+package com.blankj.myself;
+
+import java.util.Stack;
+
+import com.blankj.myself.HasCycle_fast_slow_point.ListNode;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/10/2
+ */
+public class ReverseList {
+
+    public ListNode reverseList(ListNode head) {
+        Stack<Integer> stack = new Stack();
+        while(head!=null){
+            stack.push(head.val);
+            head = head.next;
+        }
+        ListNode listNode = new ListNode(stack.pop().intValue());
+        while(!stack.isEmpty()){
+            listNode.next = new ListNode(stack.pop().intValue());
+        }
+        return listNode;
+    }
+
+}
diff --git a/src/com/blankj/myself/RomanToInt.java b/src/com/blankj/myself/RomanToInt.java
new file mode 100644
index 00000000..6d424252
--- /dev/null
+++ b/src/com/blankj/myself/RomanToInt.java
@@ -0,0 +1,41 @@
+package com.blankj.myself;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/9/21
+ */
+public class RomanToInt {
+    public int romanToInt(String s) {
+        int sum = 0;
+        int pre = cast(s.charAt(0));
+        for(int i=1;i<s.length();i++){
+            int cuur = cast(s.charAt(i));
+            if(pre<cuur){
+                sum = sum -pre;
+            }else {
+                sum = sum +pre;
+            }
+            pre = cuur;
+        }
+        sum = sum + cast(s.charAt(s.length()-1));
+        return sum;
+    }
+
+    private int cast(char i){
+        switch (i){
+            case('I'):return 1;
+            case('V'):return 5;
+            case('X'):return 10;
+            case('L'):return 50;
+            case('C'):return 100;
+            case('D'):return 500;
+            case('M'):return 1000;
+            default:return 0;
+        }
+
+    }
+}
diff --git a/src/com/blankj/myself/Rotate.java b/src/com/blankj/myself/Rotate.java
new file mode 100644
index 00000000..fea1bfc6
--- /dev/null
+++ b/src/com/blankj/myself/Rotate.java
@@ -0,0 +1,45 @@
+package com.blankj.myself;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/10/2
+ */
+public class Rotate {
+
+    public static void main(String[] args) {
+        int[] a = {1,2,3,4,5,6,7};
+        Rotate rotate = new Rotate();
+        rotate.rotate(a,3);
+    }
+
+    public void rotate(int[] nums, int k) {
+
+        for(int i=0;i<k;i++){
+            int temp = nums[nums.length-1];
+            for (int j=nums.length-1;j>=0;j--){
+                if(j==0){
+                    nums[j] = temp;
+                }else{
+                    nums[j] = nums[j-1];
+                }
+            }
+        }
+        //int[] temps = new int[k];
+        //for(int i=nums.length-k;i<=nums.length-1;i++){
+        //    temps[i+k-nums.length]=nums[i];
+        //}
+        //for(int j=nums.length-1;j>=0;j--){
+        //    if(j>=k){
+        //        nums[j]=nums[j-k];
+        //    }else{
+        //        nums[j]=temps[j];
+        //    }
+        //}
+
+    }
+
+}
diff --git a/src/com/blankj/myself/SkipLadder.java b/src/com/blankj/myself/SkipLadder.java
new file mode 100644
index 00000000..2ec24814
--- /dev/null
+++ b/src/com/blankj/myself/SkipLadder.java
@@ -0,0 +1,28 @@
+package com.blankj.myself;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/5/20
+ */
+public class SkipLadder {
+    public static void main(String[] args) {
+
+    }
+
+    public int climbStairs(int n) {
+        if(n==1){
+            return 1;
+        }
+       int[] nums = new int[n];
+       nums[0] = 1;
+       nums[1] = 2;
+       for (int i=2;i<n;i++){
+           nums[i] = nums[i-2] + nums[i-1];
+       }
+       return nums[n-1];
+    }
+}
diff --git a/src/com/blankj/myself/StackTest.java b/src/com/blankj/myself/StackTest.java
new file mode 100644
index 00000000..12a92bc3
--- /dev/null
+++ b/src/com/blankj/myself/StackTest.java
@@ -0,0 +1,35 @@
+package com.blankj.myself;
+
+import java.util.Stack;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/9/23
+ */
+public class StackTest {
+    public static void main(String[] args) {
+        StackTest stackTest = new StackTest();
+        stackTest.isValid("()");
+    }
+    public boolean isValid(String s) {
+        Stack<Character> stack = new Stack<>();
+        for(char a:s.toCharArray()){
+           if(a=='('){
+               stack.push(')');
+           }else if(a=='['){
+               stack.push(']');
+           }else if(a=='{'){
+               stack.push('}');
+           }else {
+               if(stack.pop()!=a||stack.isEmpty()){
+                   return false;
+               }
+           }
+        }
+        return stack.isEmpty();
+    }
+}
diff --git a/src/com/blankj/myself/StrStr.java b/src/com/blankj/myself/StrStr.java
new file mode 100644
index 00000000..20150b99
--- /dev/null
+++ b/src/com/blankj/myself/StrStr.java
@@ -0,0 +1,38 @@
+package com.blankj.myself;
+
+import java.util.Objects;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/10/1
+ */
+public class StrStr {
+    public static void main(String[] args) {
+        StrStr strStr = new StrStr();
+        strStr.strStr("mississippi",
+            "issip");
+    }
+
+    public int strStr(String haystack, String needle) {
+        int hLen = haystack.length();
+        int nLen = needle.length();
+
+        for (int i=0;i<hLen-nLen;i++){
+            for (int j=0; j<nLen;j++){
+                if (haystack.charAt(i+j)==needle.charAt(j)){
+                    if(j==nLen-1){
+                        return i;
+                    }
+                }else {
+                    break;
+                }
+            }
+
+        }
+        return -1;
+    }
+}
diff --git a/src/com/blankj/myself/Test.java b/src/com/blankj/myself/Test.java
new file mode 100644
index 00000000..b57f1012
--- /dev/null
+++ b/src/com/blankj/myself/Test.java
@@ -0,0 +1,15 @@
+package com.blankj.myself;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/9/10
+ */
+public class Test {
+    public static void main(String[] args) {
+        Test a = new Test();
+    }
+}
diff --git a/src/com/blankj/myself/ThreeSum.java b/src/com/blankj/myself/ThreeSum.java
new file mode 100644
index 00000000..17f83cc5
--- /dev/null
+++ b/src/com/blankj/myself/ThreeSum.java
@@ -0,0 +1,75 @@
+package com.blankj.myself;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * Description:三数之和
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/9/21
+ */
+
+/**
+ * 15. 三数之和
+ * 给你一个包含 n 个整数的数组 nums，判断 nums 中是否存在三个元素 a，b，c ，使得 a + b + c = 0 ？请你找出所有满足条件且不重复的三元组。
+
+ 注意：答案中不可以包含重复的三元组。
+
+  
+
+ 示例：
+
+ 给定数组 nums = [-1, 0, 1, 2, -1, -4]，
+
+ 满足要求的三元组集合为：
+ [
+ [-1, 0, 1],
+ [-1, -1, 2]
+ ]
+
+ 来源：力扣（LeetCode）
+ 链接：https://leetcode-cn.com/problems/3sum
+ 著作权归领扣网络所有。商业转载请联系官方授权，非商业转载请注明出处。
+ */
+public class ThreeSum {
+    public List<List<Integer>> threeSum(int[] nums) {
+        List<List<Integer>> result = new ArrayList<>();
+        Arrays.sort(nums);
+        int length = nums.length;
+        for(int k=0;k<length-2;k++){
+            if(nums[k]>0){
+                return result;
+            }
+            if(k>0&&nums[k]==nums[k-1]){
+                continue;
+            }
+            int L=k+1;
+            int R=length-1;
+            while (L<R){
+                int sum = nums[k] + nums[L] + nums[R];
+                if(sum==0){
+                    result.add(Arrays.asList(nums[k] , nums[L] , nums[R]));
+                    while (L<R &&nums[L]==nums[L+1]){
+                        L = L+1;
+                    }
+                    while (L<R &&nums[R]==nums[R-1]){
+                        R = R-1;
+                    }
+                    L = L+1;
+                    R = R-1;
+                }
+                if(sum < 0){
+                    L = L+1;
+                }
+                if(sum > 0){
+                    R = R-1;
+                }
+            }
+        }
+        return result;
+    }
+}
diff --git a/src/com/blankj/myself/ThreeThreadPrint.java b/src/com/blankj/myself/ThreeThreadPrint.java
new file mode 100644
index 00000000..72334df7
--- /dev/null
+++ b/src/com/blankj/myself/ThreeThreadPrint.java
@@ -0,0 +1,110 @@
+package com.blankj.myself;
+
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.locks.Condition;
+import java.util.concurrent.locks.ReentrantLock;
+
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/9/28
+ */
+public class ThreeThreadPrint {
+
+    public static void main(String[] args) throws InterruptedException {
+        String a = "sahjfhasjfhakjfhkjh";
+        char[] arry = a.toCharArray();
+        AtomicInteger index = new AtomicInteger();
+        ReentrantLock lock = new ReentrantLock();
+        Condition condition1 = lock.newCondition();
+        Condition condition2 = lock.newCondition();
+        Condition condition3 = lock.newCondition();
+
+
+        new Thread(()->{
+            Boolean finish = false;
+
+            try {
+
+                lock.lock();
+                while (!finish) {
+
+                    System.out.println(Thread.currentThread().getName() + ":   " + arry[index.getAndAdd(1)]);
+                    condition2.signal();
+                    condition1.await();
+
+                    if (index.get() > arry.length) {
+                        finish = true;
+                    }
+                }
+
+            }catch (Exception e){
+
+            }finally {
+                lock.unlock();
+            }
+
+        }).start();
+
+
+        new Thread(()->{
+            Boolean finish = false;
+
+            try {
+                lock.lock();
+                while (!finish) {
+                    System.out.println(Thread.currentThread().getName() + ":   " + arry[index.getAndAdd(1)]);
+
+                    condition3.signal();
+                    condition2.await();
+
+                    if (index.get() > arry.length) {
+                        finish = true;
+                    }
+                }
+
+            }catch (Exception e){
+
+            }finally {
+                lock.unlock();
+            }
+
+
+
+        }).start();
+
+        new Thread(()->{
+            Boolean finish = false;
+
+            try {
+                lock.lock();
+                while (!finish) {
+                    System.out.println(Thread.currentThread().getName() + ":   " + arry[index.getAndAdd(1)]);
+
+                    condition1.signal();
+                    condition3.await();
+
+                    if (index.get() > arry.length) {
+                        finish = true;
+                    }
+                }
+
+            }catch (Exception e){
+
+            }finally {
+                lock.unlock();
+            }
+
+
+
+        }).start();
+
+
+        Thread.sleep(100000);
+    }
+
+}
diff --git a/src/com/blankj/myself/TreeBFS.java b/src/com/blankj/myself/TreeBFS.java
new file mode 100644
index 00000000..00ad8f64
--- /dev/null
+++ b/src/com/blankj/myself/TreeBFS.java
@@ -0,0 +1,46 @@
+package com.blankj.myself;
+
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.List;
+
+import com.blankj.myself.InorderTraversal.TreeNode;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/10/3
+ */
+public class TreeBFS {
+    public List<List<Integer>> levelOrder(TreeNode root) {
+        List<List<Integer>> res = new ArrayList<>();
+        if(root==null){
+            return res;
+        }
+        ArrayDeque<TreeNode> queue = new ArrayDeque<TreeNode>();
+        queue.add(root);
+
+        while (queue.peek()!=null){
+            List<Integer> temp = new ArrayList<>();
+            int size = queue.size();
+            for (int i=0;i<size;i++){
+                TreeNode treeNode = queue.removeFirst();
+
+                if(treeNode.left != null){
+                    queue.add(treeNode.left);
+                }
+                if(treeNode.right != null){
+                    queue.add(treeNode.right);
+                }
+
+                temp.add(treeNode.val);
+            }
+
+            res.add(temp);
+        }
+        return res;
+    }
+}
diff --git a/src/com/blankj/myself/TreePostNode.java b/src/com/blankj/myself/TreePostNode.java
new file mode 100644
index 00000000..7dc05dfa
--- /dev/null
+++ b/src/com/blankj/myself/TreePostNode.java
@@ -0,0 +1,68 @@
+package com.blankj.myself;
+
+import java.util.Objects;
+import java.util.Stack;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/5/18
+ */
+
+public class TreePostNode {
+
+    public static void main(String[] args) {
+
+    }
+
+    public TreeNode inorderSuccessor(TreeNode root, TreeNode p) {
+        Stack<TreeNode> stack = new Stack<>();
+        TreeNode result = null;
+        if(Objects.nonNull(p.right)){
+            result = p.right;
+            while (Objects.nonNull(result.left)){
+                result = result.left;
+            }
+        }else {
+           stack.add(root);
+           TreeNode temp = root;
+           Boolean findFlag = false;
+           while (!findFlag){
+              if(p.val>temp.val){
+                  temp = temp.right;
+                  stack.add(temp);
+
+              }else if(p.val<temp.val){
+                  temp = temp.left;
+                  stack.add(temp);
+
+              }else {
+                  findFlag = true;
+              }
+           }
+           findFlag = false;
+           TreeNode child = p;
+           while (stack.size()>0&&!findFlag){
+               TreeNode parent = stack.pop();
+               if(child == parent.left){
+                   result = parent;
+                   findFlag = true;
+               }else {
+                   child = parent;
+               }
+           }
+
+        }
+        return result;
+    }
+
+    public class TreeNode {
+      int val;
+      TreeNode left;
+      TreeNode right;
+      TreeNode(int x) { val = x; }
+    }
+}
diff --git a/src/com/blankj/myself/TwoThreadPrint.java b/src/com/blankj/myself/TwoThreadPrint.java
new file mode 100644
index 00000000..ebaa2872
--- /dev/null
+++ b/src/com/blankj/myself/TwoThreadPrint.java
@@ -0,0 +1,86 @@
+package com.blankj.myself;
+
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.locks.Condition;
+import java.util.concurrent.locks.ReentrantLock;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/9/28
+ */
+public class TwoThreadPrint {
+
+    public static void main(String[] args) throws InterruptedException {
+        String a = "sahjfhasjfhakjfhkjhk";
+        char[] arry = a.toCharArray();
+        AtomicInteger index = new AtomicInteger();
+        ReentrantLock lock = new ReentrantLock();
+        Condition condition1 = lock.newCondition();
+        Condition condition2 = lock.newCondition();
+
+
+        new Thread(()->{
+            Boolean finish = false;
+
+                try {
+
+                    lock.lock();
+                    while (!finish) {
+
+                        System.out.println(Thread.currentThread().getName() + ":   " + arry[index.getAndAdd(1)]);
+                        condition2.signal();
+                        condition1.await();
+
+                        if (index.get() > arry.length) {
+                            finish = true;
+                        }
+                    }
+
+                }catch (Exception e){
+
+                }finally {
+                    condition2.signal();
+                    System.out.println("11111");
+                    lock.unlock();
+                }
+
+        }).start();
+
+
+        new Thread(()->{
+            Boolean finish = false;
+
+                try {
+                    lock.lock();
+                    while (!finish) {
+                        System.out.println(Thread.currentThread().getName() + ":   " + arry[index.getAndAdd(1)]);
+
+                        condition1.signal();
+                        condition2.await();
+
+                        if (index.get() > arry.length) {
+                            finish = true;
+                        }
+                    }
+
+                }catch (Exception e){
+
+                }finally {
+                    condition1.signal();
+                    System.out.println("22222");
+                    lock.unlock();
+                }
+
+
+
+        }).start();
+
+
+
+    }
+
+}