Longest Substring Without Repeating Characters

Problem Summary

Given a string s, return the length of the longest substring that contains no repeating characters.

Constraints:

The string has between 0 and 50,000 characters.
It may contain English letters, digits, symbols, and spaces.

Techniques

Hash Table
String
Sliding Window

Solution

function lengthOfLongestSubstring(s: string): number {
    let currentCharsInSubstring = new Map<string, number>()
    let maxLength = 0
    let startSubString = -1

    for (let i = 0; i < s.length; i++) {
        let currentChar = s.charAt(i)

        if (currentCharsInSubstring.has(currentChar) && currentCharsInSubstring.get(currentChar)! >= startSubString) {
            startSubString = currentCharsInSubstring.get(currentChar)!
        }

        currentCharsInSubstring.set(s.charAt(i), i)
        maxLength = Math.max(maxLength, i - startSubString)
    }

    return maxLength
};