Arrays & Hashing pattern
Two Sum
Given an array of integers and a target, return the indices of the two numbers that add up to the target. Exactly one solution exists and you may not reuse an element. Watch it run step by step, then write your own pseudocode and get it checked by AI.
- LeetCode 1
- Easy
- 2 approaches
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Arrays & HashingLeetCode 1
Easy
From the first idea to the best one
- 01 Brute force O(n²)O(1) space
- 02 Optimized · hash map O(n)O(n) space
What you will learn
- How to read Two Sum and spot the arrays & hashing pattern in it
- Brute force: O(n²) time, O(1) space
- Optimized · hash map: O(n) time, O(n) space
- The pseudocode for each approach, its line lit as the animation runs
- Practice: write your own pseudocode and get it checked
More Arrays & Hashing
See Two Sum run, step by step
Sign in and this page opens on the animation, with all 13 Arrays & Hashing problems beside it.
DSA comes with the all labs plan and every ChaiCode batch.