Meta / Amazon / Google / Microsoft| Longest Substring Without Repeating Characters | LeetCode-3: Medium | JavaScript Implementation

We will be seeing the solution to the LeetCode problem 3 in JavaScript. I hope you will find it useful.

Problem Statement:

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

Link to Problem: https://leetcode.com/problems/longest-substring-without-repeating-characters

JavaScript Implementation:

var lengthOfLongestSubstring = function(s) {
  let length = s.length 
  if(s==""){ return 0};
  let hashMap = {};
  let start = 0;
  let sub_sequnce_now = 0;
  let max_sub_sequnce_now = 0;
  for(let i = 0;i<length;i++){
      if(hashMap[s[i]] != null && (start<=hashMap[s[i]])){
          sub_sequnce_now = sub_sequnce_now-(hashMap[s[i]] - start);
          start = hashMap[s[i]]+1 
          hashMap[s[i]] = i;
      }else{
          hashMap[s[i]] = i;
          sub_sequnce_now=sub_sequnce_now+1;
          if(max_sub_sequnce_now<sub_sequnce_now){
              max_sub_sequnce_now = sub_sequnce_now
          }
      }
  }
  return max_sub_sequnce_now
};

Thank you for reading hope this code is helpful to you.