LeetCode3-无重复字符的最长子串-双指针

原题链接

Note：所有的双指针问题，优化就是想一想有没有单调性

class Solution {public: int lengthOfLongestSubstring(string s) { unordered_map heap; int res = 0; for(int i = 0, j = 0; i < s.size(); i ++){ heap[s[i]] ++; while(heap[s[i]] > 1) heap[s[j ++]] --; res = max(res, i - j + 1); } return res; }};