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题目链接https://blog.csdn.net/ayf1988/article/details/101418391

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>

using namespace std;
const int N=25;
inline int read() {
	int x=0;char ch=getchar();
	while(!isdigit(ch)) ch=getchar();
	while(isdigit(ch)){x=x*10+ch-'0';ch=getchar();}
	return x;
}
int T,num,n,m;
char mp[N][N];
bool hang[N][N],lie[N][N];
bool tg(int l,int r,int n) {
	int ans1=0,ans2=0;
	char a[N],b[N];
	for(int i=1;i<=n;i++)
		a[i]=a[i+n]=mp[l][i],b[i]=b[i+n]=mp[r][i];
	for(int i=1,j=2;i<=n&&j<=n;) {
		int k=0;
		for(;k<n&&a[i+k]==a[j+k];k++);
		if(k==n) break;
		if(a[j+k]>a[i+k]) swap(i,j);
		i=i+k+1;
		i+=i==j?1:0;
		ans1=j;
	}
	for(int i=1,j=2;i<=n&&j<=n;) {
		int k=0;
		for(;k<n&&b[i+k]==b[j+k];k++);
		if(k==n) break;
		if(b[j+k]>b[i+k]) swap(i,j);
		i=i+k+1;
		i+=i==j?1:0;
		ans2=j;
	}
	for(int i=0;i<n;i++)
		if(a[i+ans1]!=b[i+ans2]) return 0;
	return 1;
}
char s1[N],s2[N];
bool vis1[N],vis2[N];
bool flag;
inline void check() {
    for (int i=1;i<=n;i++)
        for (int j=1;j<=m;j++)
            if (mp[s2[i]][s1[j]]!=mp[s2[n-i+1]][s1[m-j+1]]) return;
    printf("YES\n");
    flag=1;
}
void solve_lie(int pos,int op) {
	if(flag) return;
	if(pos==0) {check();return;}
	if(op) {
		for(int i=1;i<=m;i++) {
			vis1[i]=1;
			s1[pos]=i;
			solve_lie(pos-1,0);
			vis1[i]=0;
		}
	} else {
		for(int i=1;i<=m;i++) {
			if(vis1[i]) continue;
			for(int j=i+1;j<=m;j++) 
				if(!vis1[j]&&lie[i][j]) {
					vis1[i]=1;vis1[j]=1;
					s1[pos]=i;s1[m-pos+1]=j;
					solve_lie(pos-1,0);
					vis1[i]=0;vis1[j]=0;
				}			
			return;		
		}
	}
}
void solve_hang(int pos,int op) {
	if(flag) return;
	if(pos==0) {solve_lie((m+1)/2,m&1);return;}
	if(op) {
		for(int i=1;i<=n;i++) {
			vis2[i]=1;
			s2[pos]=i;
			solve_hang(pos-1,0);
			vis2[i]=0;
		}
	} else {
		for(int i=1;i<=n;i++) {
			if(vis2[i]) continue;
			for(int j=i+1;j<=n;j++) 
				if(!vis2[j]&&hang[i][j]) {
					vis2[i]=1;vis2[j]=1;
					s2[pos]=i;s2[n-pos+1]=j;
					solve_hang(pos-1,0);
					vis2[i]=0;vis2[j]=0;
				}	
			return;				
		}
	}
}
int main() {
	num=read();T=read();
	while(T--) {
		n=read();m=read();
		for(int i=1;i<=n;i++)
			scanf("%s",mp[i]+1);
		        for (int i=1;i<=n;i++)
            for (int j=1;j<=n;j++) {
                static char x[N],y[N];
                for (int k=1;k<=m;k++)
                    x[k]=mp[i][k],
                    y[k]=mp[j][k];
                sort(x+1,x+m+1);
                sort(y+1,y+m+1);
                hang[i][j]=1;
                for (int k=1;k<=m;k++)
                    if(x[k]!=y[k]) hang[i][j]=0;
            }
            for (int i=1;i<=m;i++)
                for (int j=1;j<=m;j++) {
                    static char x[N],y[N];
                    for (int k=1;k<=n;k++)
                        x[k]=mp[k][i],
                        y[k]=mp[k][j];
                    sort(x+1,x+n+1);
                    sort(y+1,y+n+1);
                    lie[i][j]=1;
                    for (int k=1;k<=n;k++)
                        if (x[k]!=y[k]) lie[i][j]=0//排序判断字符串重构
                }
		flag=0;
		solve_hang((n+1)/2,n&1);
		if(!flag) puts("NO");
	}
	return 0;
}