Determining If a Pair of Integers in an Array Sums to a Target Value

Problem

Given an array of integers and a target value, determine if there is a pair of integers in the array that sums to the target value.
Example input: [3, 5, 2, -4, 8, 11], 7
Example output: True (3 + 4 = 7)

Solution

This solution is in C++. Our A.I. can create solutions in multiple languages.

kayakane

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

using namespace std;

bool sum_exists(vector<int>& arr, int target) {
    unordered_map<int, int> map;
    for (int i = 0; i < arr.size(); i++) {
        if (map.find(arr[i]) != map.end()) {
            return true;
        }
        map[target - arr[i]] = i;
    }
    return false;
}

int main() {
    vector<int> arr = {3, 5, 2, -4, 8, 11};
    int target = 7;
    cout << sum_exists(arr, target) << endl;
    return 0;
}