[못품/릿코드/javascript]3. Longest Substring Without Repeating Characters

var lengthOfLongestSubstring = function(s) {
    let map = {};
    let start = 0;
    let max = 0;
    for(let i=0;i<s.length;i++){
        start = start<=map[s[i]] ? map[s[i]]+1 : start
        map[s[i]] = i;
        max = Math.max(i-start+1,max)
    }
    return max
};