直接按照题意模拟即可

#include <iostream>
#include <algorithm>
#include <cstring>
#include <vector>
#include <cstdio>
#include <unordered_map>
#include <queue>
#include <deque>
#include <cmath>
#include <set>
#include <stack>
#include <map>
using namespace std;
//#define int long long
signed main()
{
	int t;
	scanf("%d",&t);
	while(t--)
	{
		int n;
		scanf("%d",&n);
		string s1;
		cin >> s1;
		int m;
		scanf("%d",&m);
		string s2;
		cin >> s2;
		string ss=s1;
		string k;
		cin >> k;
		int len=k.length();
		for(int i=0;i<len;i++)
		{
			if(k[i]=='D')
			{
				ss=ss+s2[i];
			}
			else
				ss=s2[i]+ss;
		}
		cout << ss << endl;
	}	
	return 0;
}

#include <stdio.h>
#include <string.h>
int main(){
    int t;
    scanf("%d",&t);
    while(t--){
        int m,n;
        char s[200] = {0};
        char b[100] = {0};
        char c[100] = {0};
        scanf("%d",&n);
        scanf("%s",s);
        scanf("%d",&m);
        scanf("%s",b);
        scanf("%s",c);
        int ls = strlen(s);//让ls等于s的字符串长度实际上也与n相等
        for(int i = 0; i < m; i++){
            if(c[i]=='V'){
                for(int j=ls;j>0;j--){
                    s[j]=s[j-1];
                }
                s[0]=b[i];
                ls++;
            }
            else if(c[i]=='D'){
                s[ls]=b[i];
                ls++;
            }
        }
        printf("%s\n",s);
    }
}