Longest Substring Without Repeating Characters

Description

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.

 

Constraints:

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

Solution(javascript)

/**
 * @param {string} s
 * @return {number}
 */
var lengthOfLongestSubstring = function(s) {
    let chars = [];
    let left = 0;
    let right = 0;
    let res = 0;
    while (right < s.length) {
        let r = s.charAt(right);
        let index = chars[r];
        if(index !== null && index >= left && index < right) {
            left = index + 1;
        }
        res = Math.max(res, right - left + 1);
        chars[r] = right;
        right++
    }
    return res;
};