应该是输出反了，改一下就过了
```
#include<string>
#include<cstdio>
#include<cstring>
#include<string>
#include<iostream>
using namespace std;
int main(){
string c;
char a[1000],o[1000];
int k,y=0,x;
cin>>k>>c>>x;
long long ans=0;
for(int i=0;i<c.length();i++){
if(c[i]>='A'&&c[i]<='Z'){
ans=ans*k+c[i]-'A'+10;
}
else ans=ans*k+c[i]-'0';
}
while(ans!=0){
y++;
o[y]=ans%x;
if(o[y]>9)o[y]=o[y]+'A'-10;
else o[y]=o[y]+'0';
ans/=x;
}
for(int i=y;i>=1;i--)cout<<o[i];
return 0;
}
```
by glx123 @ 2023-08-20 17:26:50