1069. The Black Hole of Numbers

#include <stdio.h>#include <math.h>/*递减减递增的*/int main(){int num, i=0, x[5], y[5], large,small,ans=0,temp,j;scanf("%d",&num);while (ans != 6174) {for (i = 0; i < 4;i++) {temp = num % 10;num /= 10;for (j = i; j > 0; j--) {if (x[j - 1] > temp)break;else x[j] = x[j - 1];}x[j] = temp;}large = x[0] * 1000 + x[1] * 100 + x[2] * 10 + x[3];small = x[0] + x[1] * 10 + x[2] * 100 + x[3] * 1000;ans = large - small;printf("%04d - %04d = %04d\n", large, small, ans);if (!ans) break;num = ans;}return 0;}