Steps to Find the Longest Substring Without Repeating Characters

Different Approaches to Look Out For

Given a string S. The task is to find the length of the longest substring without repeating characters.

Ready to dive in?

Problem Statement

Examples-  Input: S = “abcabcbb”  Output: 3   Explanation: “abc” is the longest substring without repeating characters.

Explore more examples for a better understanding

The idea is to generate all substrings of the given string and then return the length of the longest substring that has all unique characters.

Check out the algorithm

Approach 1: Bruteforce Approach

Time Complexity: O(N^3), where N is the string length. Space Complexity: O(min(N, M)), where M is the size of the substrings.

Want to explore other approaches?

If a substring S[i][j] from index i to j – 1 has already been checked to have no duplicate characters, then simply check if S[j] is a substring of S[i][j].

Approach 2: Sliding Window Approach

Check out the algorithm

Time Complexity: O(N^2), where N is the string length.  Space Complexity: O(min(N,M)), as a visiting array is used

How to optimise this approach?

Start your journey now and learn how to find the longest substring without repeating characters.

Ready to level up your coding skills?

Step Up Your Game with InterviewBit Web Stories

Don't miss out on the chance to upskill yourself with IntervewBit's engaging web stories. 

“