Ruudukko

#include <bits/stdc++.h>
#define F first
#define S second
using namespace std;
typedef long long ll;

 mt19937 gen(1337);

int check(int n, int m, const vector<int>& perm){
	for (int i=0;i<n;i++){
		for (int j=0;j<m;j++){
			if (i+1<n){
				if (abs(perm[i*m+j]-perm[i*m+m+j])<=1) return 0;
			}
			if (j+1<m){
				if (abs(perm[i*m+j]-perm[i*m+j+1])<=1) return 0;
			}
		}
	}
	return 1;
}

void solve(){
	int n,m;
	cin>>n>>m;
	vector<int> perm(n*m);
	for (int i=0;i<n*m;i++){
		perm[i]=i+1;
	}
	for (int it=0;it<1000;it++){
		shuffle(perm.begin(), perm.end(), gen);
		if (check(n,m,perm)){
			cout<<"YES"<<endl;
			for (int i=0;i<n;i++){
				for (int j=0;j<m;j++){
					cout<<perm[i*m+j]<<" ";
				}
				cout<<endl;
			}
			return;
		}
	}
	cout<<"NO"<<endl;
}

int main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int t;
	cin>>t;
	for (int tc=0;tc<t;tc++){
		solve();
	}
}

Test 1

Verdict: ACCEPTED