1047. Remove All Adjacent Duplicates In String

方法1 stack

class Solution {
    public String removeDuplicates(String s) {
        StringBuilder sb = new StringBuilder();
        Stack<Character> stack = new Stack<>();
        for (char c : s.toCharArray()) {
            if (stack.isEmpty() || c != stack.peek()) {
                stack.push(c);
            } else {
                stack.pop();
            }
        }
        while (!stack.isEmpty()) {
           sb.insert(0, stack.pop());
        }
        return sb.toString();
    }
}

方法2 直接操作sb,replace

class Solution {
    public String removeDuplicates(String s) {
        StringBuilder sb = new StringBuilder();
        for (char c : s.toCharArray()) {
            if (sb.length() - 1 >= 0 && c == sb.charAt(sb.length() - 1)) {
                sb.deleteCharAt(sb.length() - 1);
            } else {
                sb.append(c);
            }
        }

        return sb.toString();
    }
}