Two Sum (Sorted Array)

Arrays & Two-Pointerseasy

Course · Section 11: Working With Arrays · Lecture 149: Simple Array Methods

Given a **sorted** array `nums` and a `target`, return the 0-based indices `[i, j]` of the two numbers that add up to `target`. Exactly one solution exists. Example: `twoSum([1, 2, 4, 7], 6)` → `[1, 2]`.

Sample tests

Input: twoSum([1,2,4,7], 6)

Output: [1,2]

Input: twoSum([2,7,11,15], 9)

Output: [0,1]

+ 2 hidden tests run on Submit.

Hints

Common pitfalls

A nested loop is O(n^2); the sorted order is what lets you avoid it.

Learning resources

MDN: Arrays

Approach & explanation (try first)

Two pointers start at the ends and move inward based on the sum versus target. O(n) time, O(1) space.

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