Easy Algorithms

Two sum

Array Hash Table

57.1% acceptance

Feb 27, 2026

67856

2524

Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target. You may assume that each input would have exactly one solution, and you may not use the same element twice. You can return the answer in any order.

Solution

Rust

Time O(n)

Space O(n)

LeetCode

solution.rs

impl Solution {
  pub fn two_sum(nums: Vec<i32>, target: i32) -> Vec<i32> {
    let mut map = std::collections::HashMap::new();
    for (i, &num) in nums.iter().enumerate() {
      let complement = target - num;
      if let Some(&j) = map.get(&complement) {
        return vec![j, i as i32];
      }
      map.insert(num, i as i32);
    }
    vec![]
  }
}