Majority Element of an Array

#include <iostream>
#include <vector>
using namespace std;

int main() {
    vector<int> vec = { 2, 7, 11, 15 };

    int target = 22;
    int st = 0, end = vec.size() - 1;

    while (st < end) {
        if (target > (vec[st] + vec[end])) {
            st++;
        }
        else if (target < (vec[st] + vec[end])) {
            end--;
        }
        else {
            cout << st << ", " << end << endl;
            return 0;
        }
    }

    return -1;
}