leetcode

0 class Solution {

1 public:

2 string removeDuplicateLetters(string s) {

3 uint16_t last[128] = {0}, seen[128] = {0};

4 string res = "";

5

6 for (int i = 0; i < s.size(); i++)

7 last[s[i]] = i;

8 for (int i = 0; i < s.size(); i++) {

9 if (seen[s[i]]++) continue;

10 while (!res.empty() && res.back() > s[i] && i < last[res.back()]) {

11 seen[res.back()] = 0;

12 res.pop_back();

13 }

14 res.push_back(s[i]);

15 }

16 return res;

17 }

18 };