Submission #968898

#	Time	Username	Problem	Language	Result	Execution time	Memory
968898		happy_node	Furniture (JOI20_furniture)	C++17	100 / 100	1614 ms	72968 KiB

furniture

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

const int MX=1005;

int N,M,Q;
int C[MX][MX], deg[MX][MX], rdeg[MX][MX];

set<pair<int,int>> st[2*MX];

void dfs(int x, int y) {
	if(x+1<=N && !C[x+1][y]) {
		deg[x+1][y]-=1;
		if(deg[x+1][y]==0) {
			st[x+1+y-2].erase({x+1,y});
			C[x+1][y]=1;
			dfs(x+1,y);
		}
	}

	if(y+1<=M && !C[x][y+1]) {
		deg[x][y+1]-=1;
		if(deg[x][y+1]==0) {
			st[x+y+1-2].erase({x,y+1});
			C[x][y+1]=1;
			dfs(x,y+1);
		}
	}
}
	
void rdfs(int x, int y) {
	if(x-1>=1 && !C[x-1][y]) {
		rdeg[x-1][y]-=1;
		if(rdeg[x-1][y]==0) {
			st[x-1+y-2].erase({x-1,y});
			C[x-1][y]=1;
			rdfs(x-1,y);
		}
	}
	if(y-1>=1 && !C[x][y-1]) {
		rdeg[x][y-1]-=1;
		if(rdeg[x][y-1]==0) {
			st[x+y-1-2].erase({x,y-1});
			C[x][y-1]=1;
			rdfs(x,y-1);
		}
	}
}

bool r[MX][MX], rr[MX][MX];

int main() {
	cin.tie(0); ios_base::sync_with_stdio(0);

	cin>>N>>M;

	for(int i=1;i<=N;i++) {
		for(int j=1;j<=M;j++) {
			cin>>C[i][j];
		}
	}

	r[1][1]=1;
	for(int i=1;i<=N;i++) {
		for(int j=1;j<=M;j++) {
			if(C[i][j]) continue;
			if(!r[i][j]) continue;
			r[i+1][j]|=r[i][j];
			r[i][j+1]|=r[i][j];
			deg[i][j+1]+=1;
			deg[i+1][j]+=1;
		}
	}

	rr[N][M]=1;
	for(int i=N;i>=1;i--) {
		for(int j=M;j>=1;j--) {
			if(C[i][j]) continue;
			if(!rr[i][j]) continue;
			rr[i-1][j]|=rr[i][j];
			rr[i][j-1]|=rr[i][j];
			rdeg[i-1][j]+=1;
			rdeg[i][j-1]+=1;
		}
	}

	for(int i=1;i<=N;i++) {
		for(int j=1;j<=M;j++) {
			if(C[i][j]) {
				r[i][j]=0;
				rr[i][j]=0;
			}
		}
	}

	for(int i=1;i<=N;i++) {
		for(int j=1;j<=M;j++) {
			if(r[i][j] && rr[i][j]) {
				st[i+j-2].insert({i,j});
			}
		}
	}

	cin>>Q;

	for(int i=1;i<=Q;i++) {
		int x,y;
		cin>>x>>y;

		if(!st[x+y-2].count({x,y})) {
			cout<<1<<endl;
			continue;
		}

		if(st[x+y-2].size()==1) {
			cout<<0<<endl;
			continue;
		}

		st[x+y-2].erase({x,y});
		C[x][y]=1;
		dfs(x,y);
		rdfs(x,y);

		cout<<1<<endl;
	}

}

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