LeetCode 3. Longest Substring Without Repeating Characters (javascript)

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

Example 1:

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

Example 2:

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

Example 3:

Input: s = "pwwkew"
Output: 3
Explanation: The answer is "wke", with the length of 3.
Notice that the answer must be a substring, "pwke" is a subsequence and not a substring.

Example 4:

Input: s = ""
Output: 0

Constraints:

• 0 <= s.length <= 5 * 104
• s consists of English letters, digits, symbols and spaces.

Solutions:

/**
 * @param {string} s
 * @return {number}
 */
var lengthOfLongestSubstring = function(s) {
    let n = s.length;
    let ans = 0;
    let visited = new Map();
    for (let i = 0; i < n; i++) {
        for (let j = i; j < n ; j++) {
            if (visited.has(s[j])) {
                visited.clear();
                break;
            } else {
                ans = Math.max(ans, j - i + 1);
                visited.set(s[j], true);
            }
            
        }
        
    }
    return ans;
};