RemoveAllAdjacentDuplicatesInString.java

package io.ziheng.stack.leetcode;

import java.util.Deque;
import java.util.LinkedList;

/**
 * LeetCode 1047. Remove All Adjacent Duplicates In String
 * https://leetcode.com/problems/remove-all-adjacent-duplicates-in-string/
 */
public class RemoveAllAdjacentDuplicatesInString {
    public String removeDuplicates(String S) {
        if (S == null) {
            return S;
        }
        char[] charArr = S.toCharArray();
        Deque<Character> stack = new LinkedList<>();
        for (char c : charArr) {
            if (!stack.isEmpty() && stack.peek() == c) {
                stack.pop();
                continue;
            }
            stack.push(c);
        }
        StringBuilder sb = new StringBuilder();
        while (!stack.isEmpty()) {
            sb.append(stack.pop());
        }
        return sb.reverse().toString();
    }
}
/* EOF */