#3 - Longest Substring Without Repeating Characters

Medium • View on LeetCode • View on GitHub

Problem Description

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

Solution

/**
 * @param {string} s
 * @return {number}
 */
var lengthOfLongestSubstring = function(s) {
  const map = {};
  let offset = 0;

  return s.split('').reduce((max, value, i) => {
    offset = map[value] >= offset ? map[value] + 1 : offset;
    map[value] = i;
    return Math.max(max, i - offset + 1);
  }, 0);
};