纯暴力

#include<iostream>
#include<queue>
#include<stack>
#include<math.h>
#include<string.h>
using namespace std;
char map[60][60];
int n,m;
void bfs(int b,int a){
	if(map[b][a]=='*'&&map[b+1][a]=='*'&&map[b+1][a+1]=='*'&&map[b-1][a]!='*'&&map[b-1][a+1]!='*'&&map[b-1][a-1]!='*'&&map[b][a-1]!='*'&&map[b][a+1]!='*'&&map[b][a+2]!='*'&&map[b+1][a-1]!='*'&&map[b+1][a+2]!='*'&&map[b+2][a]!='*'&&map[b+2][a-1]!='*'&&map[b+2][a+1]!='*'&&map[b+2][a+2]!='*'){
		map[b][a]='.';
		map[b+1][a]='.';
		map[b+1][a+1]='.';
	}else if(map[b][a]=='*'&&map[b][a+1]=='*'&&map[b+1][a+1]=='*'&&map[b-1][a-1]!='*'&&map[b-1][a]!='*'&&map[b-1][a+1]!='*'&&map[b][a+2]!='*'&&map[b][a-1]!='*'&&map[b][a+2]!='*'&&map[b+1][a]!='*'&&map[b+1][a-1]!='*'&&map[b+1][a+2]!='*'&&map[b+2][a]!='*'&&map[b+2][a+1]!='*'&&map[b+2][a+2]!='*'){
		map[b][a]='.';
		map[b][a+1]='.';
		map[b+1][a+1]='.';
	}else if(map[b][a]=='*'&&map[b+1][a]=='*'&&map[b+1][a-1]=='*'&&map[b-1][a]!='*'&&map[b-1][a-1]!='*'&&map[b-1][a+1]!='*'&&map[b][a-2]!='*'&&map[b][a-1]!='*'&&map[b][a+1]!='*'&&map[b+1][a-2]!='*'&&map[b+1][a+1]!='*'&&map[b+2][a]!='*'&&map[b+2][a-1]!='*'&&map[b+2][a-2]!='*'&&map[b+2][a+1]!='*'){
		map[b][a]='.';
		map[b+1][a]='.';
		map[b+1][a-1]='.';
	}else if(map[b][a]=='*'&&map[b][a+1]=='*'&&map[b+1][a]=='*'&&map[b-1][a]!='*'&&map[b-1][a-1]!='*'&&map[b-1][a+2]!='*'&&map[b-1][a+1]!='*'&&map[b][a-1]!='*'&&map[b][a+2]!='*'&&map[b+1][a-1]!='*'&&map[b+1][a+1]!='*'&&map[b+1][a+2]!='*'&&map[b+2][a]!='*'&&map[b+2][a+1]!='*'&&map[b+2][a-1]!='*'){
		map[b][a]='.';
		map[b][a+1]='.';
		map[b+1][a]='.';
	}
}
int main(){
	int t;
	scanf("%d", &t);
	while(t--){
		memset(map,0,sizeof(map));
		int temp=1;
		scanf("%d %d", &n, &m);
		for(int i=1;i<=n;i++){
			for(int j=1;j<=m;j++){
				cin>>map[i][j];	
			}
		}
		for(int i=1;i<=n;i++){
			for(int j=1;j<=m;j++){
				if(map[i][j]=='*'){
					bfs(i,j);
				}
			}
		}
		for(int i=1;i<=n;i++){
			for(int j=1;j<=m;j++){
				if(map[i][j]=='*'){
					temp=0;
				}
			}
		}
		if(temp==0){
			printf("NO\n");
		}else{
			printf("YES\n");
		}
	}
	
}