摘要：
class Solution { public String removeDuplicateLetters(String s) { int n = s.length(); if(n <= 1) return s; Stack<Character> stack = new Stack<>(); for 阅读全文
摘要：
解法一： #include <bits/stdc++.h> using namespace std; const int N = 30030; int a[N], f[N], b[N]; int n; int main() { while(cin >> a[n]) n++; int res = 0, 阅读全文