AC代码

#include<bits/stdc++.h>
using namespace std;
int main(){
    cout<<"ABCDEFGHIJKLMNOPQR"<<endl;
    cout<<"BABCDEFGHIJKLMNOPQ"<<endl;
    cout<<"CBABCDEFGHIJKLMNOP"<<endl;
    cout<<"DCBABCDEFGHIJKLMNO"<<endl;
    cout<<"EDCBABCDEFGHIJKLMN"<<endl;
    cout<<"FEDCBABCDEFGHIJKLM"<<endl;
    cout<<"GFEDCBABCDEFGHIJKL"<<endl;
    cout<<"HGFEDCBABCDEFGHIJK"<<endl;
    cout<<"IHGFEDCBABCDEFGHIJ"<<endl;
    cout<<"JIHGFEDCBABCDEFGHI"<<endl;
    return 0;
}