#include<iostream>
using namespace std;
int main(){
    int h = 10;
    int l = 18;
    //第一层循环遍历行
    for(int i = 1;i <= h;i++){
        char a1 = 'A' + i - 1;
        char a2 = a1;
        //内部第一层循环遍历倒着到A
        for(char a3 = 'A';a2>=a3;a2--){
            cout<<a2;
            //最后一列停止循环
            if(l==1) break;
            l--;
        }
        //遍历后面的列
        char a4 = 'B';
        while(l!=0){
            cout<<a4;
            a4 = a4 + 1;
            l--;
        }
        cout<<endl;
        l = 18;
    }
    return 0;
}

#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; }

`