3SUM

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

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

int main() {
  ll n, x;
  cin >> n >> x;
  for (int i = 0; i < n; ++i) {
    int k;
    cin >> k;
    T[i] = k;
  }
  sort(T,T+n);
  for (int i = 0; i < n; ++i) {
    for (int j = i+1; j < n; ++j) {
      ll k = x - T[i] - T[j];
      if (S.count(k)) {
        cout << T[i] << ' ' << T[j] << ' ' << k << '\n';
        return 0;
      }
    }
    S.insert(T[i]);
  }
  cout << "IMPOSSIBLE\n";
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

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: TIME LIMIT EXCEEDED

Test 23

Verdict: ACCEPTED