Sliding Window pattern
Longest Substring Without Repeats
Given a string, find the length of the longest contiguous substring that contains no repeated characters. Watch it run step by step, then write your own pseudocode and get it checked by AI.
- LeetCode 3
- Medium
- 3 approaches
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Sliding WindowLeetCode 3
Medium
From the first idea to the best one
- 01 Brute force · restart on duplicate O(n²)O(charset) space
- 02 Better · sliding window with set O(n)O(charset) space
- 03 Optimized · jump L via last-seen map O(n)O(charset) space
What you will learn
- How to read Longest Substring Without Repeats and spot the sliding window pattern in it
- Brute force · restart on duplicate: O(n²) time, O(charset) space
- Better · sliding window with set: O(n) time, O(charset) space
- Optimized · jump L via last-seen map: O(n) time, O(charset) space
- The pseudocode for each approach, its line lit as the animation runs
- Practice: write your own pseudocode and get it checked
More Sliding Window
- Longest Repeating Character ReplacementLC 424 · Medium
- Minimum Window SubstringLC 76 · Hard
- Permutation in StringLC 567 · Medium
- Sliding Window MaximumLC 239 · Hard
- OverviewConcept
- Max Sum Subarray of Size KLC 643 · Easy
- Max Sum of Distinct Subarrays, Size KLC 2461 · Medium
- Max Points From CardsLC 1423 · Medium
See Longest Substring Without Repeats run, step by step
Sign in and this page opens on the animation, with all 8 Sliding Window problems beside it.
DSA comes with the all labs plan and every ChaiCode batch.