3.Leetcode Longest Substring Without Repeating Characters

题目

Given a string, find the length of the longest substring without repeating characters.

Example 1:

Input: “abcabcbb”
Output: 3
Explanation: The answer is “abc”, with the length of 3.

解题方法

借助unordered_set来实现最大连续无重复字符串，基础知识参考我的博客

class Solution {
public:
    int lengthOfLongestSubstring(string s) {
      int res = 0, left = 0, i = 0, n = s.size();
      unordered_set<char> t;
        while (i < n) {
            if (!t.count(s[i])) {
                t.insert(s[i++]);
                res = max(res, (int)t.size());
            }  else {
                t.erase(s[left++]);
            }
        }
        return res;
    }
};