#Leetcode# 3. Longest Substring Without Repeating Characters

https://leetcode.com/problems/longest-substring-without-repeating-characters/description/

 

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. 

Example 2:

Input: "bbbbb"
Output: 1
Explanation: The answer is "b", with the length of 1.

Example 3:

Input: "pwwkew"
Output: 3
Explanation: The answer is "wke", with the length of 3. 
             Note that the answer must be a substring, "pwke" is a subsequence and not a substring.

代码：

class Solution {
public:
    int lengthOfLongestSubstring(string s) {
        map<char, int> mp;
        mp.clear();
        int ans = 0, l = 0;
        for(int i = 0; i < s.length(); i ++) {
            if(mp[s[i]] == 0 || mp[s[i]] < l)
                ans = max(ans, i - l + 1);
            else l = mp[s[i]];
            
            mp[s[i]] = i + 1;
        }
        return ans;
    }
};