Master Coding & Crack Tech Interviews with CodeForge

#include <vector>
#include <unordered_map>
#include <iostream>

std::vector<int> twoSum(std::vector<int>& nums, int target) {
    std::unordered_map<int, int> seen;
    for (int i = 0; i < nums.size(); i++) {
        int diff = target - nums[i];
        if (seen.count(diff)) return {seen[diff], i};
        seen[nums[i]] = i;
    }
    return {};
}