不知道为什么，下载下来自己测是对的，但是是WA,和p1957一样 希望有大佬可以答疑解惑

#include <bits/stdc++.h>
using namespace std;
string r[105];
int s = 0;
string x, y, z;
int o, p, q;
int main(){
	int q;
	cin >> q;
	string a;
	cin >> a;
	char choice; 
	for(int i = 0; i < q; i++){
		fflush(stdin);
		choice = getchar();
		switch(choice){
			case '1':
				cin >> x;
				a += x;
				r[s++] = a;
				break;
			case '2':
				z = "";
				cin >> o >> p;
				for(int j = o; j <=o+p-1; j++){
					z += a[j];
				}
				r[s++] = z;
				a = z;
				break;
			case '3':
				z = "";
				cin >> o >> y;
				for(int j = o; j < a.length(); j++){
					z += a[j];
				}
				a.replace(o, y.length(), y);
				a += z;
				r[s++] = a;
				break;
			case '4':
				cin >> x;
				o = a.find(x);
				if(o < 0 || o >= a.length()){
					o = -1;
				}
				r[s++] = to_string(o);
		}
	}
	for(int i = 0; i < s; i++){
		cout << r[i] << endl;
	}
	
	return 0;
}