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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#127870#6644. Red Black Grid45645ATL 1ms12556kbC++141.7kb2023-07-20 10:47:182023-07-20 10:47:19

Judging History

你现在查看的是最新测评结果

  • [2023-08-10 23:21:45]
  • System Update: QOJ starts to keep a history of the judgings of all the submissions.
  • [2023-07-20 10:47:19]
  • 评测
  • 测评结果:TL
  • 用时:1ms
  • 内存:12556kb
  • [2023-07-20 10:47:18]
  • 提交

answer

#include <bits/stdc++.h>
using namespace std;
const int N=1010;
inline int read()
{
	char ch;
	while((ch=getchar())<'0'||ch>'9');
	int res=ch-'0';
	while((ch=getchar())>='0'&&ch<='9') res=res*10+ch-'0';
	return res;
}
int n,K,a[N][N];
bool dfs(int x,int y,int now)
{
	if(now>K) return 0;
	if(x==n)
	{
		if(now==K)
		{
			for(int i=0;i<n;printf("\n"),i++)
				for(int j=0;j<n;j++)
				printf("%c",a[i][j]?'R':'B');
			return 1;
		}
		return 0;
	}
	a[x][y]=0;
	int tmp=now+(x&&a[x-1][y]!=a[x][y])+(y&&a[x][y-1]!=a[x][y]);
	if(y==n-1?dfs(x+1,0,tmp):dfs(x,y+1,tmp)) return 1;
	a[x][y]=1;
	tmp=now+(x&&a[x-1][y]!=a[x][y])+(y&&a[x][y-1]!=a[x][y]);
	if(y==n-1?dfs(x+1,0,tmp):dfs(x,y+1,tmp)) return 1;
	return 0;
}
struct node{
	int x,y;
	node(int a=0,int b=0){
		x=a,y=b;
	}
};
int val(node u){
	return 4-(u.x==0||u.x==n-1)-(u.y==0||u.y==n-1); 
}
bool operator<(node a,node b){ return val(a)>val(b); }
node d[N*N];
int tot;
bool dfs2(int now,int rst)
{
	if(!rst) return 1;
	if(now>tot) return 0;	
	if(val(d[now])>rst) return 0;
	a[d[now].x][d[now].y]=1;
	if(dfs2(now+1,rst-val(d[now]))) return 1;
	a[d[now].x][d[now].y]=0;
	return dfs2(now+1,rst);
}
int main()
{
	int T=read();
	while(T--)
	{
		n=read(),K=read();
		if(K==1||K==2*(n-1)*n-1) printf("Impossible\n");
		else
		{
			printf("Possible\n");
			if(n<=3) dfs(0,0,0);
			else
			{
				for(int i=0;i<n;i++)
					for(int j=0;j<n;j++)
					{
						a[i][j]=0;
						if(!((i+j)&1)) d[++tot]=node(i,j);	
					}		
				sort(d+1,d+1+tot);
				dfs2(1,K);
				for(int i=0;i<n;printf("\n"),i++)
					for(int j=0;j<n;j++)
					printf("%c",a[i][j]?'R':'B');
			}
		}
	}
	return 0;
}

Details

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Test #1:

score: 100
Accepted
time: 1ms
memory: 12556kb

input:

2
3 6
3 1

output:

Possible
BBB
BBR
BRB
Impossible

result:

ok correct! (2 test cases)

Test #2:

score: -100
Time Limit Exceeded

input:

4424
1 0
2 4
2 3
2 2
2 1
2 0
3 12
3 11
3 10
3 9
3 8
3 7
3 6
3 5
3 4
3 3
3 2
3 1
3 0
4 24
4 23
4 22
4 21
4 20
4 19
4 18
4 17
4 16
4 15
4 14
4 13
4 12
4 11
4 10
4 9
4 8
4 7
4 6
4 5
4 4
4 3
4 2
4 1
4 0
5 40
5 39
5 38
5 37
5 36
5 35
5 34
5 33
5 32
5 31
5 30
5 29
5 28
5 27
5 26
5 25
5 24
5 23
5 22
5 21
5...

output:

Possible
B
Possible
BR
RB
Impossible
Possible
BB
BR
Impossible
Possible
BB
BB
Possible
BRB
RBR
BRB
Impossible
Possible
BBR
BRB
RBR
Possible
BBB
RBR
BRB
Possible
BBB
BRB
RBR
Possible
BBB
BRR
RBB
Possible
BBB
BBR
BRB
Possible
BBB
BBR
RBB
Possible
BBB
BBB
RBR
Possible
BBB
BBB
BRB
Possible
BBB
BBB
BBR
I...

result: