LeetCode: 3. Longest substring without repeating characters

topic

Given a string, find the length of the longest substring that does not contain repeating characters.

Example 1:

Input: s = "abcabcbb"
Output: 3
Explanation: Since the longest substring without repeating characters is "abc", its length is 3.
Example 2:

Input: s = "bbbbb"
Output: 1
Explanation: Since the longest substring without repeating characters is "b", its length is 1.
Example 3:
Input: s = "pwwkew"
Output: 3

Example 4:
Input: s = ""
Output: 0

Hint:
0 <= s.length <= 5 * 104
s consists of English letters, numbers, symbols and spaces

answer

code

/**
 * @param {string} s
 * @return {number}
 */
var lengthOfLongestSubstring = function(s) {
    let start = 0,end = 0;
    let mp = new Map();
    let ans = 0;
    while(end<s.length)
    {
        
        let pos = mp.get(s[end]);
        if(mp.has(s[end])&&pos>=start)
        {
            start = mp.get(s[end])+1;
        }
        mp.set(s[end],end);
        ans = Math.max(ans,end-start+1);
        end++;
    }
    return ans;
};