Ice_Cream_Parlor.cpp

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

class IceCream {
    
    public: 
        int flavor; 
        int index;

        IceCream(int flavor, int index) {
            this->flavor = flavor;
            this->index = index;
       }
       bool operator < (const IceCream& ic2) {
            return (this->flavor < ic2.flavor);
       }
};

int binarySearch(int first, int last, vector<IceCream> arr, int search) {
   //if(first == last) return first;
   while (first <= last) {
       int mid = (first + last) / 2;
       if (search == arr[mid].flavor) return arr[mid].index;
       else if(search > arr[mid].flavor) first = mid + 1;
       else last = mid - 1;
   }
   return -1;
}

int main() {
    int t;
    int n, m;
    cin >> t;
    for(int test = 0; test < t; test++) {       
        cin >> m >> n;
        vector<IceCream> arr;
        arr.reserve(n); 

        for (int i = 0; i < n; i++) {
            int cost;
            cin >> cost;
            arr.push_back(IceCream(cost, i + 1));
        }

        sort(arr.begin(), arr.end());
        int firstIndex = 100000, secondIndex = 100000;
        for(int i = 0; i < n - 1 ; i++) {
            int search = m - arr[i].flavor;
            if(search >= arr[i].flavor) {
                int index = binarySearch( i + 1, n - 1, arr, search);
                if( index != -1 ) {
                    cout << min(arr[i].index, index) << " " << max(arr[i].index, index) << endl;
                    break;

                }
            }
        }

    }

}