pat1069 The Black Hole of Numbers

#include<cstdio>#include<iostream>#include<algorithm>#include<vector>#include<queue>#include<string>#include<cstring>#include<cmath>#include<map>using namespace std;int l(int n){int bit[5];int ret = 0;bit[0] = n%10,n/=10;bit[1] = n%10,n/=10;bit[2] = n%10,n/=10;bit[3] = n%10;sort(bit,bit+4);for(int i = 0;i<4;i++){ret*=10;ret+=bit[i];}return ret;}int h(int n){int bit[5];int ret = 0;bit[0] = n%10,n/=10;bit[1] = n%10,n/=10;bit[2] = n%10,n/=10;bit[3] = n%10;sort(bit,bit+4);for(int i = 3;i>=0;i--){ret*=10;ret+=bit[i];}return ret;}int main(){int n,m;while(scanf("%d",&n)!=EOF){m = n;while(1){int hh = h(n),ll = l(n);n = hh-ll;if(n == 0){printf("%04d - %04d = 0000\n",m,m);break;}printf("%04d - %04d = %04d\n",hh,ll,n);if(n == 6174)break;}}    return 0;}