Ruudukko

#include <bits/stdc++.h>
using namespace std;
 
set<int> w[101];
set<int> h[101];
 
int main() {
	int n;
	cin >> n;
 
	for (int j = 1; j < 101; ++j) {
		for (int i = 1; i <= n*2; ++i) {
			w[j].insert(i);
			h[j].insert(i);
		}
	}
 
	int z = -1;
	for (int y = 1; y <= n; ++y) {
		for (int x = 1; x <= n; ++x) {
			auto itw = w[y].begin();
			auto ith = h[x].begin();
 
			while (true) {
				if (itw == w[y].end() || ith == h[x].end()) {
					cout << "QAQ\n";
					return 0;
				}
				/**
				cout << '\n';
				cout << x << " " << y << '\n';
				cout << *itw << " " << *ith << '\n';
				cout << "cw: " << w[y].count(*ith) << ", ch: " << h[x].count(*itw) << '\n';
				*/
				if (*itw >= *ith) {
					z = *itw;
					if (h[x].count(z) == 1) {
						h[x].erase(h[x].find(z));
						w[y].erase(w[y].find(z));
						break;
					} else ++ith;
				} else {
					z  = *ith;
					if (w[y].count(z) == 1) {
						w[y].erase(w[y].find(z));
						h[x].erase(h[x].find(z));
						break;
					} else ++itw;
				}
			}
			//cout << '\n';
			cout << z << " ";
		}
		cout << '\n';
	}
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED