Submission #690049

#	Time	Username	Problem	Language	Result	Execution time	Memory
690049		iskhakkutbilim	Red-blue table (IZhO19_stones)	C++14	32 / 100	78 ms	3144 KiB

stones

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

//#define int long long
#define ff first
#define ss second
#define all(a) a.begin(), a.end()
int n, m, t;
int calc(vector<vector<int> > &a){
	int all = 0;
	for(int i = 0;i < n; i++){
		int blue = 0;
		for(int j = 0;j < m; j++){
			blue+= a[i][j];
		}
		if(blue >= m-(m / 2) and blue > m/2) all++;
	}
	for(int j = 0;j < m; j++){
		int red = 0;
		for(int i = 0;i < n; i++){
			red+= (a[i][j] == 0);
		}
		if(red >= n-(n / 2) and red > n/2) all++;
	}
	return all;
}


void solve(){
	 cin >> n >> m;
	vector< vector<int> > a(n, vector<int>(m,0));
	if(t <= 16 and max(n, m)<= 4){
		int answer = 0, s = 0, MASK=0;
		vector<pair<int,int>> cell(n*m);
		for(int i = 0;i < n; i++){
			for(int j = 0;j < m; j++){
				cell[s] = {i, j};
				s++;
			}
		}
		for(int mask = 0; mask < (1<<(n*m)); mask++){
			for(int i = 0;i < n*m; i++){
				if(mask & (1<<i)){
					a[cell[i].ff][cell[i].ss] = 1;
				}else{
					a[cell[i].ff][cell[i].ss] = 0;
				}
			}
			int S = calc(a);
			
			if(answer < S){
				answer = S;
				MASK = mask;
			}
		}
		for(int i = 0;i < n*m; i++){
			if(MASK & (1<<i)){
				a[cell[i].ff][cell[i].ss] = 1;
			}else{
				a[cell[i].ff][cell[i].ss] = 0;
			}
		}
		cout << answer << '\n';
		for(int i = 0;i < n; i++){
			for(int j = 0;j < m; j++){
				cout << (a[i][j] ? '+' : '-'); 
			}
			cout << '\n';
		}
		return;
	}
 	set<pair<int, int> > st;
	vector< pair<int, int> > del;
	for(int i = 0;i < m; i++){
		st.insert({0, i});
	}
	int need = max(n / 2+1, n-(n / 2));
	for(int i = 0;!st.empty() and i < n; i++){
		int cnt = need;
		for(pair<int, int> x : st){
			if(cnt == 0) break;
			cnt--;
			if(x.ff== n-need){
				st.clear();
				break;
			}
			a[i][x.ss] = 1;
			del.push_back(x);
		}
		for(pair<int, int> x : del){
			st.erase(x);
			st.insert({x.ff+1, x.ss});
		}
		del.clear();
	}
	cout << calc(a) << '\n';
	for(int i = 0;i < n; i++){
		for(int j = 0;j < m; j++){
			cout << (a[i][j] ? '+' : '-');
		}
		cout << '\n';
	}
}


main(){
   ios::sync_with_stdio(0);
   cin.tie(0); cout.tie(0);
	cin >> t;
	while(t--){
		solve();
	}

	return 0;
}

Compilation message (stderr)

stones.cpp:106:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  106 | main(){
      | ^~~~

• Subtask 1: 17 / 17
• Subtask 2: 0 / 10
• Subtask 3: 0 / 16
• Subtask 4: 0 / 11
• Subtask 5: 15 / 15
• Subtask 6: 0 / 31