[Algorithm] 43 week(11.21 ~ 11.27) 3/3

3. Longest Substring Without Repeating Characters

var lengthOfLongestSubstring = function(s) {
    const used = {}
    let maxCount = 0;
    let start = 0;

    for(let i = 0; i < s.length; i++){
        if(used[s[i]]){
            start = Math.max(start, used[s[i]]);
        }
        
        maxCount = Math.max(maxCount, i - start + 1);
        used[s[i]] = i + 1;
    }

    return maxCount;
};