snippets

#include <unordered_map>
#include <vector>

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