add 1544

Author: fishercoder1534

README.md

@@ -8,6 +8,7 @@ _If you like this project, please leave me a star._ ★
 
 |  #  |      Title     |   Solutions   | Video  | Difficulty  | Tag                   
 |-----|----------------|---------------|--------|-------------|-------------
+|1544|[Make The String Great](https://leetcode.com/problems/make-the-string-great/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1544.java) | |Easy|String, Stack|
 |1541|[Minimum Insertions to Balance a Parentheses String](https://leetcode.com/problems/minimum-insertions-to-balance-a-parentheses-string/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1541.java) | |Medium|String, Stack|
 |1539|[Kth Missing Positive Number](https://leetcode.com/problems/kth-missing-positive-number/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1539.java) | |Easy|Array, HashTable|
 |1535|[Find the Winner of an Array Game](https://leetcode.com/problems/find-the-winner-of-an-array-game/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1535.java) | [:tv:](https://youtu.be/v6On1TQfMTU) |Medium|Array|

src/main/java/com/fishercoder/solutions/_1544.java

@@ -0,0 +1,46 @@
+package com.fishercoder.solutions;
+
+import java.util.Stack;
+
+public class _1544 {
+    public static class Solution1 {
+        public String makeGood(String s) {
+            Stack<Character> stack = new Stack<>();
+            for (int i = 0; i < s.length() - 1; i++) {
+                char c = s.charAt(i);
+                if (stack.isEmpty()) {
+                    stack.add(c);
+                } else {
+                    if (Character.toLowerCase(stack.peek()) == Character.toLowerCase(c)) {
+                        if ((Character.isLowerCase(stack.peek()) && Character.isUpperCase(c))) {
+                            stack.pop();
+                        } else if (Character.isUpperCase(stack.peek()) && Character.isLowerCase(c)) {
+                            stack.pop();
+                        } else {
+                            stack.add(c);
+                        }
+                    } else {
+                        stack.add(c);
+                    }
+                }
+            }
+            char c = s.charAt(s.length() - 1);
+            if (!stack.isEmpty() && Character.toLowerCase(stack.peek()) == Character.toLowerCase(c)) {
+                if ((Character.isLowerCase(stack.peek()) && Character.isUpperCase(c))) {
+                    stack.pop();
+                } else if (Character.isUpperCase(stack.peek()) && Character.isLowerCase(c)) {
+                    stack.pop();
+                } else {
+                    stack.add(c);
+                }
+            } else {
+                stack.add(c);
+            }
+            StringBuilder sb = new StringBuilder();
+            while (!stack.isEmpty()) {
+                sb.append(stack.pop());
+            }
+            return sb.reverse().toString();
+        }
+    }
+}

src/test/java/com/fishercoder/_1544Test.java

@@ -0,0 +1,32 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._1544;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class _1544Test {
+    private static _1544.Solution1 solution1;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _1544.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        assertEquals("leetcode", solution1.makeGood("leEeetcode"));
+    }
+
+    @Test
+    public void test2() {
+        assertEquals("", solution1.makeGood("abBAcC"));
+    }
+
+    @Test
+    public void test3() {
+        assertEquals("s", solution1.makeGood("s"));
+    }
+
+}