2 ways of solving "Longest Substring Without Repeating Characters" problem in JavaScript

longestSubstringWithoutRepeatingCharacters.js

// //BRUTE FORCE METHOD
// var lengthOfLongestSubstring = function(s) {
    
//     let count = 0;

//     for (let i=0; i< s.length; i++) {
//         let char = s.charAt(i);
//         let set = new Set([char]);

//         for (let j=i+1; j<s.length; j++) {
//             let char = s.charAt(j);
//             if (set.has(char)) {
//                 break;
//             } else {
//                 set.add(char);
//             }

//             count = Math.max(count, set.size);
//         }
//     }

//     return count;
// };

//SLIDING WINDOW METHOD
var lengthOfLongestSubstring = function(s) {
    
    let count = 0;

    let i = 0;
    let j = 0;
    let n = s.length;
    let set = new Set();

    while (i < n && j < n) {
        let char = s.charAt(j);
        if(!set.has(char)) {
            set.add(char);
            j++;
            count = Math.max (count, j - i);
        } else {
            set.delete(s.charAt(i));
            i++;
        }
    }

    return count;
};

let result = lengthOfLongestSubstring('abcabcbb')
console.log(result);