debug中...
public String removeDuplicateLetters(String s) {//1.去掉重复字母做准备，存储记录字符数量。int[] arr = new int[26];for (char c : s.toCharArray()) {arr[c - 'a']++;}//StringBuilder ans=new StringBuilder(26);Stack<Character> ans = new Stack<>();//用队列也可boolean[] inAns = new boolean[26];for (char c : s.toCharArray()) {arr[c - 'a']--;if (ans.isEmpty() || arr[c - 'a'] == 0) {ans.push(c);inAns[c - 'a'] = true;}if (inAns[c - 'a']) {continue;}char ch = ans.peek();//注意这应该是while// 输入：s = "cbacdcbc"//输出："acdb"if (c < ch && arr[ch - 'a'] > 0) {inAns[ch - 'a'] = false;ans.pop();}ans.push(c);inAns[c - 'a'] = true;}StringBuilder str=new StringBuilder();while (!ans.isEmpty()){str.append(ans.pop());}return str.reverse().toString();}chatgpt修复后：
