100%AC题解（内存较少）

#include<iostream>
#include<string>
using namespace std;
char c[]{'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'};//一个一个给它打出来
string to_r(int a,int r){
    string s,s1="";
    while(a){
        s+=c[a%r];
        a/=r;
    }
    for(int i=s.size()-1;i>=0;i--)s1+=s[i];
    return s1;
}
int main(){
    int a,b,r;
    cin>>a>>b>>r;
    string a1=to_r(a,r);
    string b1=to_r(b,r);
    if(a1>b1)cout<<a1;
    else cout<<b1;
    return 0;
}