3-longest-substring-without-repeating Characters

Longest Substring Without Repeating Characters

Given a string, find the length of thelongest substringwithout repeating characters.

*Example 1:*
*Input:*”abcabcbb”
*Output:*3
*Explanation:* The answer is “abc”, with the length of 3.

*Example 2:*
*Input:*”bbbbb”
*Output:*1
*Explanation:*The answer is “b”, with the length of 1.

*Example 3:*
*Input:*”pwwkew”
*Output:*3
*Explanation:*The answer is “wke”, with the length of 3.
             Note that the answer must be a *substring*, “pwke” is a /subsequence/ and not a substring.

solution:

function lenOfLongStr(s) {
  let map = {};

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

  return value;
}