# ICECREAM-PARLOR hackerrank Solution - Correct, Optimal and Working

``````/*
*  Author: Arpit Bhayani
*  https://arpitbhayani.me
*/
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <climits>
#include <deque>
#include <iostream>
#include <list>
#include <limits>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <vector>

#define ll long long

#define MIN(a, b) a < b ? a : b
#define MAX(a, b) a > b ? a : b

using namespace std;

int i = 0;
char ch;
while((ch = getchar()) != '\n') {
str[i++] = ch;
}
str[i] = '\0';
return i;
}

int arr[100010];
map<int, vector<int> > m;
int main(int argc, char *argv[]) {
int t;
scanf("%d", &t);

while(t--) {
m.clear();
int sum, n;
scanf("%d%d", &sum, &n);
for(int i = 1 ; i <= n; i++) {
scanf("%d", &arr[i]);
m[arr[i]].push_back(i);
}

int ans1 = 0, ans2 = 0;
for(int i = 1; i <= n; i++) {
int vala = arr[i];
int valb = sum - arr[i];
vector<int> indexa, indexb;

map<int, vector<int> >::iterator itra = m.find(vala);
map<int, vector<int> >::iterator itrb = m.find(valb);

if(itra != m.end() && itrb != m.end()) {
indexa = itra->second;
indexb = itrb->second;
if(vala == valb && indexa.size() >= 2) {
ans1 = indexa[0];
ans2 = indexa[1];
break;
}
else if(vala == valb && indexa.size() < 2) {
// Nothing
}
else if(vala != valb) {
ans1 = indexa[0];
ans2 = indexb[0];
break;
}
}
}

if(ans1 > ans2) {
int t = ans1;
ans1 = ans2;
ans2 = t;
}
printf("%d %d\n", ans1, ans2);
}

return 0;
}
``````