Submission #546011

#	Time	Username	Problem	Language	Result	Execution time	Memory
546011		8e7	Furniture (JOI20_furniture)	C++17	100 / 100	302 ms	17996 KiB

furniture

//Challenge: Accepted
#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
using namespace std;
#ifdef zisk
void debug(){cout << endl;}
template<class T, class ... U> void debug(T a, U ... b){cout << a << " ", debug(b...);}
template<class T> void pary(T l, T r) {
	while (l != r) cout << *l << " ", l++;
	cout << endl;
}
#else
#define debug(...) 0
#define pary(...) 0
#endif
#define ll long long
#define maxn 1005
#define pii pair<int, int>
#define ff first
#define ss second
#define io ios_base::sync_with_stdio(0);cin.tie(0);
int a[maxn][maxn], cnt[2*maxn];
int dir[4][2] = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};

bool vis[maxn][maxn], vis2[maxn][maxn];

int n, m;
bool in(int x, int y){return x >= 0 && x < n && y >= 0 && y < m;} 

bool good(int x, int y){return in(x, y) && vis[x][y];}
void dfs(int x, int y) {
	vis[x][y] = 0;	
	cnt[x+y]--;
	for (int k = 0;k < 4;k++) {
		int nx = x + dir[k][0], ny = y + dir[k][1];
		if (in(nx, ny) && vis[nx][ny] && !(nx == 0 && ny == 0) && !(nx == n - 1 && ny == m - 1)) {
			if (!(good(nx + 1, ny) || good(nx, ny+1)) || !(good(nx-1, ny) || good(nx, ny-1))) {
				dfs(nx, ny);
			}	
		}
	}		
}
int main() {
	io
	cin >> n >> m;
	for (int i = 0;i < n;i++) {
		for (int j = 0;j < m;j++) {
			cin >> a[i][j];
		}
	}
	queue<pii> que;
	que.push({0, 0});	
	vis[0][0] = 1;
	auto add = [&] (int x, int y){
		if (in(x, y) && !vis[x][y] && !a[x][y]) {
			que.push({x, y});
			vis[x][y] = 1;
		}
	};
	while (que.size()) {
		pii cur = que.front();que.pop();
		add(cur.ff + 1, cur.ss);
		add(cur.ff, cur.ss+1);
	}	
	for (int i = 0;i < n;i++) {
		for (int j = 0;j < m;j++) {
			vis2[i][j] = vis[i][j];
			vis[i][j] = 0;
		}
	}
	que.push({n-1, m-1});	
	vis[n-1][m-1] = 1;
	while (que.size()) {
		pii cur = que.front();que.pop();
		add(cur.ff - 1, cur.ss);
		add(cur.ff, cur.ss-1);
	}
	for (int i = 0;i < n;i++) {
		for (int j = 0;j < m;j++) {
			vis[i][j] &= vis2[i][j];
			if (vis[i][j]) cnt[i+j]++;
		}
	}	
	int q;
	cin >> q;
	while (q--) {
		int x, y;
		cin >> x >> y; x--, y--;
		if (vis[x][y] && cnt[x+y] == 1) {
			cout << 0 << "\n";	
		} else {
			if (vis[x][y]) dfs(x, y);
			cout << 1 << "\n";
		} 
	}
}

• Subtask 1: 5 / 5
• Subtask 2: 95 / 95