1069. The Black Hole of Numbers (20)

#include <string>#include<algorithm>#include <vector>#include <sstream>#include <iostream>using namespace std;bool cmp1(char  a,char b){return a>b;}bool cmp2(char a,char b){return a<b;}int a,b;stringstream ss,ss1,ss2;void solve(int n){ss.clear();string s2="",s3="";string s1="";string s4="";int c=1000;int d;  for(int i=0;i<4;i++)  {    if(n/c==0)  s1+='0';  else{  d=n/c;string tmp="";  ss.clear();  ss<<d;  ss>>tmp;  s1+=tmp;}    n=n%c;  c/=10;  }vector<char>v1,v2;for(int i=0;i<4;i++){v1.push_back(s1[i]);v2.push_back(s1[i]);}sort(v1.begin(),v1.end(),cmp1);sort(v2.begin(),v2.end(),cmp2);for(int i=0;i<4;i++){s2+=v1[i];s3+=v2[i];}ss1.clear();ss2.clear();ss1<<s2;ss2<<s3;ss1>>a;ss2>>b;}int main(){ int n;cin>>n;if(n==0)printf("0000 - 0000 = 0000");else{solve(n);while(a-b!=6174&&a-b!=0){ printf("%.4d - %.4d = %.4d\n",a,b,a-b);solve(a-b);}printf("%.4d - %.4d = %.4d\n",a,b,a-b);}return 0;}