refactor 386

Author: fishercoder1534

src/main/java/com/fishercoder/solutions/_386.java

@@ -1,107 +1,40 @@
 package com.fishercoder.solutions;
 
 import java.util.ArrayList;
-import java.util.Collections;
-import java.util.Comparator;
-import java.util.Date;
 import java.util.List;
 
 /**
+ * 386. Lexicographical Numbers
+ *
  * Given an integer n, return 1 - n in lexicographical order.
-
-For example, given 13, return: [1,10,11,12,13,2,3,4,5,6,7,8,9].
-
-Please optimize your algorithm to use less time and space. The input size may be as large as 5,000,000.*/
+ *
+ * For example, given 13, return: [1,10,11,12,13,2,3,4,5,6,7,8,9].
+ *
+ * Please optimize your algorithm to use less time and space. The input size may be as large as
+ * 5,000,000.
+ */
 public class _386 {
-    //Radix sort doesn't apply here! Don't confuse myself!
-    
-    //rewrote their solution from Python to Java:https://discuss.leetcode.com/topic/54986/python-memory-limit-exceeded-for-problem-386/17
-    public static List<Integer> lexicalOrder(int n) {
-        List<Integer> result = new ArrayList();
-        int i = 1;
-        while (true) {
-            result.add(i);
-            if (i * 10 <= n) {
-                i *= 10;
-            } else {
-                while (i % 10 == 9 || i == n) {
-                    i /= 10;
-                }
-                if (i == 0) {
-                    return result;
-                }
-                i++;
-            }
-        }
-    }
-
-    //someone on Discuss hinted that you could use recursion to solve it in Java
-    //then I wrote the following method, eventually, got all test cases produce the right output, but unfortunately TLE'ed by OJ
-    public static List<Integer> lexicalOrder_LTE_by_10458(int n) {
-        List<Integer> result = new ArrayList();
-        int insertPosition = 0;
-        return addNumbers(result, 1, insertPosition, n);
-    }
-
-    private static List<Integer> addNumbers(List<Integer> result, int insertNumber, int insertPosition, int n) {
-        int i;
-        for (i = 0; i < 9; i++) {
-            if (insertNumber + i > n) {
-                return result;
-            }
-            result.add(insertPosition + i, insertNumber + i);
-            if ((insertNumber + i) % 10 == 0 && (insertNumber + i) == (insertNumber + 10)) {
-                break;
-            }
-        }
-        while ((insertNumber + i) % 10 != 0 && (insertNumber + i) <= n) {
-            result.add(insertPosition + i, insertNumber + i);
-            i++;
-        }
-        //find next insert position:
-        insertPosition = result.indexOf((insertNumber + i) / 10);
-        return addNumbers(result, insertNumber + i, insertPosition + 1, n);
-    }
-
-    public static void main(String... strings) {
-        long lStartTime = new Date().getTime();
+  public static class Solution1 {
+    //Radix sort doesn't apply here! Don't confuse yourself!
 
-//      CommonUtils.printList(lexicalOrder_TLE_by_23489(23489));
-//        List<Integer> result = lexicalOrder(1);//right
-//        List<Integer> result = lexicalOrder(13);//right
-//        List<Integer> result = lexicalOrder_LTE_by_10458(58);
-//        List<Integer> result = lexicalOrder(120);//right  
-//        List<Integer> result = lexicalOrder(1200);
-//        List<Integer> result = lexicalOrder(10);
-//        List<Integer> result = lexicalOrder(5000000);
-//        List<Integer> result = lexicalOrder_LTE_by_10458(50000);//this can finish in 183 ms
-        List<Integer> result = lexicalOrder_LTE_by_10458(500000);
-//        List<Integer> result = lexicalOrder_LTE_by_10458(14959);
-        long lEndTime = new Date().getTime();
-        long difference = lEndTime - lStartTime;
-        System.out.println("Elapsed milliseconds: " + difference);
-        System.out.println("result size is: " + result.size());
-//        CommonUtils.printList(result);
-    }
-
-    /**
-     * The most naive way is to generate this list, sort it using a customized comparator and then return it.
-     * Unfortunately, this results in TLE with this input: 23489
-     */
-    public static List<Integer> lexicalOrder_TLE_by_23489(int n) {
-        List<Integer> result = new ArrayList();
-        for (int i = 1; i <= n; i++) {
-            result.add(i);
+    //rewrote their solution from Python to Java:https://discuss.leetcode.com/topic/54986/python-memory-limit-exceeded-for-problem-386/17
+    public List<Integer> lexicalOrder(int n) {
+      List<Integer> result = new ArrayList();
+      int i = 1;
+      while (true) {
+        result.add(i);
+        if (i * 10 <= n) {
+          i *= 10;
+        } else {
+          while (i % 10 == 9 || i == n) {
+            i /= 10;
+          }
+          if (i == 0) {
+            return result;
+          }
+          i++;
         }
-        Collections.sort(result, new Comparator<Integer>() {
-            @Override
-            public int compare(Integer o1, Integer o2) {
-                String s1 = String.valueOf(o1);
-                String s2 = String.valueOf(o2);
-                return s1.compareTo(s2);
-            }
-        });
-        return result;
+      }
     }
-
+  }
 }