//31B3683
#include<algorithm>
#include<iostream>
#include<cstring>
#include<string>
#include<iomanip>
#include<cstdio>
#include<cmath>
#include<stack>
#include<queue>
using namespace std;
int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin>>n;
    for(int i=1;i<=n;i++){
        int l,a;
        cin>>l>>a;
        string s1,s2;
        cin>>s1>>s2;
        if(s1==s2){
            cout<<"Yes\n";
            if(a==0){
                continue;
            }
            for(int j=1;j<=a;j++){
                int o,p;
                char c;
                cin>>o>>p>>c;
                if(o==0){
                    s1[p-1]=c;
                    if(s1==s2){
                        cout<<"Yes\n";
                    }
                    else{
                        cout<<"No\n";
                    }
                }
                if(o==1){
                    s2[p-1]=c;
                    if(s1==s2){
                        cout<<"Yes\n";
                    }
                    else{
                        cout<<"No\n";
                    }
                }
            }
        }
        else{
            cout<<"No\n";
            if(a==0){
                continue;
            }
            for(int j=1;j<=a;j++){
                int o,p;
                char c;
                cin>>o>>p>>c;
                if(o==0){
                    s1[p-1]=c;
                    if(s1==s2){
                        cout<<"Yes\n";
                    }
                    else{
                        cout<<"No\n";
                    }
                }
                if(o==1){
                    s2[p-1]=c;
                    if(s1==s2){
                        cout<<"Yes\n";
                    }
                    else{
                        cout<<"No\n";
                    }
                }
            }
        }
    }
    return 0;
}