3SUM

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

const int N = 5000;
set<ll> S;
int T[N];

int main() {
  ll n, x;
  cin >> n >> x;
  for (int i = 0; i < n; ++i) {
    int x;
    cin >> x;
    T[i] = x;
  }
  for (int i = 0; i < n; ++i) {
    for (int j = i; j < n; ++j) {
      if (S.count(x - T[i] - T[j])) {
        cout << T[i] << ' ' << T[j] << ' ' << x - T[i] - T[j] << '\n';
        return 0;
      }
    }
    S.insert(T[i]);
  }
  cout << "IMPOSSIBLE\n";
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: ACCEPTED

Test 4

Verdict: WRONG ANSWER

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: WRONG ANSWER

Test 8

Verdict: WRONG ANSWER

Test 9

Verdict: WRONG ANSWER

Test 10

Verdict: ACCEPTED

Test 11

Verdict: WRONG ANSWER

Test 12

Verdict: WRONG ANSWER

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: WRONG ANSWER

Test 17

Verdict: WRONG ANSWER

Test 18

Verdict: WRONG ANSWER

Test 19

Verdict: ACCEPTED

Test 20

Verdict: WRONG ANSWER

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: WRONG ANSWER