3_longest_subscrting_without_repeating_characters.cpp

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

 

//Example 1:

//Input: s = "abcabcbb"
//Output: 3
//Explanation: The answer is "abc", with the length of 3.

//Example 2:

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

//Example 3:

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

//Constraints:

//    0 <= s.length <= 5 * 104
//    s consists of English letters, digits, symbols and spaces.

class Solution {
public:
    int lengthOfLongestSubstring(string s) {
        map<char, int> window;
        
        int res = 0;
        
        for(int i = 0, j = 0; j < s.size(); j++){
            if(window.find(s[j]) != window.end()){
                i = max(i, window[s[j]]+1);
            }
            res = max(res, j-i+1);
            window[s[j]] = j;
        }
        
        return res;
    }
};