3. Longest Substring Without Repeating Characters - JS

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Description

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

Example

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


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


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.

Solution

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let lengthOfLongestSubstring = function(s) {
    let set = new Set();
    let l = 0, r = 0, max = 0;
    
    while( r < s.length ){
        if( !set.has(s[r]) ){
            set.add(s[r]);
            max = Math.max(max, r-l+1);
            r++;
        }else{
            while( set.has(s[r]) ) {
              set.delete(s[l]);
              l++;
            }
        }
    }
    return max;
};