题解

#include <bits/stdc++.h>
using namespace std;
int main(){
    string s;
    cin>>s;
    for(int i=0;i<=s.size();i++){
        if(s[i]=='a' || s[i]=='c' || s[i]=='g' || s[i]=='o'){
            s[i]-=32;
        }else if(s[i]>=97 && s[i]<=122){
            
        }else if(s[i]=='A' || s[i]=='C' || s[i]=='G' || s[i]=='O'){
            
        }else if(s[i]=='B' || s[i]=='D' || s[i]=='E' || s[i]=='F' || s[i]=='H' || s[i]=='I' || s[i]=='J' || s[i]=='K' || s[i]=='L' || s[i]=='M' || s[i]=='N' || s[i]=='P' || s[i]=='Q' || s[i]=='R' || s[i]=='S' || s[i]=='T' || s[i]=='U' || s[i]=='V' || s[i]=='W' || s[i]=='X' || s[i]=='Y' || s[i]=='Z'){
            s[i]+=32;
        }
    }
    cout<<s;
    return 0;
}