问题:1069. The Black Hole of Numbers (20)
#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
using namespace std;
int main()
{
string n,m;
cin>>n;
if(n.size()!=4) n=string(4-n.size(),'0')+n;
m=n;
sort(m.begin(),m.end(),greater<char>());
sort(n.begin(),n.end());
if(m==n)
{
cout<<m<<" - "<<n<<" = "<<"0000"<<endl;
return 0;
}
while(true)
{
string ans=to_string(stoi(m)-stoi(n));
if(ans.size()!=4) ans=string(4-ans.size(),'0')+ans;
cout<<m<<" - "<<n<<" = "<<ans<<endl;
if(ans=="6174") return 0;
m=n=ans;
sort(m.begin(),m.end(),greater<char>());
sort(n.begin(),n.end());
}
return 0;
}