Summat

input/code.cpp: In function 'int main()':
input/code.cpp:31:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < cand.size(); ++i) {
                 ~~^~~~~~~~~~~~~

#include <iostream>
#include <set>
#include <vector>

using namespace std;



int main() {
	int n;
	cin >> n;
	multiset<int> B;
	for(int i = 1; i <= (n*(n-1))/2; ++i) {
		int s;
		cin >> s;
		B.insert(s);
	}
	vector<int> cand;
	auto it = B.begin();
	int B0 = *it;
	++it;
	int B1 = *it;
	++it;
	for(; it != B.end(); ++it) {
		int x = B0 + B1 - (*it);
		if(x <= 0) break;
		if(x%2 != 0) continue;
		x/=2;
		cand.push_back(x);
	}
	for(int i = 0; i < cand.size(); ++i) {
		bool w = true;
		multiset<int> C = B;
		vector<int> A;
		A.push_back(cand[i]);
		int t = 1;
		while(t < n) {
			auto it = C.begin();
			int j = (*it) - cand[i];
			for(int a = 0; a < t; ++a) {
				if(C.count(A[a] + j) == 0) {
					w = false;
					break;
				}
				it = C.lower_bound(A[a] + j);
				C.erase(it);
			}
			if(!w) break;
			++t;
			A.push_back(j);
		}
		if(w) {
			for(int j = 1; j <= n; ++j) {
				cout << A[j-1] << " ";
			}
			cout << "\n";
			return 0;
		}

	}
}

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 1, 2, 3

Verdict: ACCEPTED

Test 3

Group: 1, 2, 3

Verdict: ACCEPTED

Test 4

Group: 1, 2, 3

Verdict: ACCEPTED

Test 5

Group: 1, 2, 3

Verdict: ACCEPTED

Test 6

Group: 2, 3

Verdict: ACCEPTED

Test 7

Group: 2, 3

Verdict: ACCEPTED

Test 8

Group: 2, 3

Verdict: ACCEPTED

Test 9

Group: 2, 3

Verdict: ACCEPTED

Test 10

Group: 2, 3

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED