Find two numbers that sum to a target
Company: Agoda
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: medium
Interview Round: Technical Screen
### Array sum lookup
Given an integer array `nums` and an integer `target`, find **two distinct indices** `i` and `j` such that:
- `nums[i] + nums[j] == target`
- `i != j`
Return the pair of indices (in any order). If no such pair exists, return an empty result.
#### Clarifications to confirm in interview
- Are there negative numbers? (Assume yes.)
- If multiple answers exist, can we return any one? (Assume yes.)
- What output format is expected (0-based indices, 1-based indices, or the values themselves)? Specify and be consistent.
#### Constraints (typical)
- `1 <= nums.length <= 1e5`
- `-1e9 <= nums[i], target <= 1e9`
Quick Answer: This question evaluates array manipulation, index-based reasoning, and algorithmic problem-solving skills related to identifying value pairs that meet a numeric target.
Return two distinct 0-based indices whose values sum to target, or [] if none exists.
Examples
Input: ([2, 7, 11, 15], 9)
Expected Output: [0, 1]
Explanation: Classic.
Input: ([3, 3], 6)
Expected Output: [0, 1]
Explanation: Duplicate values.