test9.js

/*
Sliding Window - findLongestSubstring
Write a function called findLongestSubstring, which accepts a string and returns the length of the longest substring with all distinct characters.

findLongestSubstring('') // 0
findLongestSubstring('rithmschool') // 7
findLongestSubstring('thisisawesome') // 6
findLongestSubstring('thecatinthehat') // 7
findLongestSubstring('bbbbbb') // 1
findLongestSubstring('longestsubstring') // 8
findLongestSubstring('thisishowwedoit') // 6

Time Complexity - O(n)
*/

const findLongestSubstring = str => {
  let start = 0;
  let seen = {};
  let longest = 0;
  for (i = 0; i < str.length; i++) {
    let char = str[i];
    if (seen[char]) {
      start = Math.max(start, seen[char]);
    }
    longest = Math.max(longest, i - start + 1);
    seen[char] = i + 1;
  }
  return longest;
};

console.log(findLongestSubstring('longestsubstring'));