Pat1069代码
For any 4-digit integer except the ones with all the digits being the same, if we sort the digits in non-increasing order first, and then in non-decreasing order, a new number can be obtained by taking the second number from the first one. Repeat in this manner we will soon end up at the number 6174 -- the "black hole" of 4-digit numbers. This number is named Kaprekar Constant.
For example, start from 6767, we'll get:
7766 - 6677 = 1089
9810 - 0189 = 9621
9621 - 1269 = 8352
8532 - 2358 = 6174
7641 - 1467 = 6174
... ...
Given any 4-digit number, you are supposed to illustrate the way it gets into the black hole.
Input Specification:
Each input file contains one test case which gives a positive integer N in the range (0, 10000).
Output Specification:
If all the 4 digits of N are the same, print in one line the equation "N - N = 0000". Else print each step of calculation in a line until 6174 comes out as the difference. All the numbers must be printed as 4-digit numbers.
Sample Input 1:6767Sample Output 1:
7766 - 6677 = 1089 9810 - 0189 = 9621 9621 - 1269 = 8352 8532 - 2358 = 6174Sample Input 2:
2222Sample Output 2:
2222 - 2222 = 0000
#include<cstdio>
#include<functional>
#include<algorithm>
using namespace std;
int main(int argc,char *argv[])
{
int Max[4],Min[4];
int maxnum,minnum;
int n;
int i,j;
scanf("%d",&n);
do
{
for(i=0;i<4;i++)
{
Max[i]=Min[i]=n%10;
n/=10;
}
sort(Max,Max+4,greater<int>());
sort(Min,Min+4);
maxnum=minnum=0;
for(i=0;i<4;i++)
{
maxnum=maxnum*10+Max[i];
minnum=minnum*10+Min[i];
}
n=maxnum-minnum;
printf("%04d - %04d = %04d\n",maxnum,minnum,n);
}while(n!=0&&n!=6174);
return 0;
}