6174问题排序搜索

# include <stdio.h># include <string.h>int num[2000];int count;int get_next(int x){    int a,b,n;    char s[10];    sprintf(s,"%d",x);    n=strlen(s);    for(int i=0;i<n;i++)        for(int j=i+1;j<n;j++)        if(s[i]>s[j])    {        char t=s[i];        s[i]=s[j];        s[j]=t;    }    sscanf(s,"%d",&b);    for(int i=0;i<n/2;i++)    {        char t=s[i];        s[i]=s[n-1-i];        s[n-1-i]=t;    }    sscanf(s,"%d",&a);    return a-b;}int main(){    scanf("%d",&num[0]);    printf("%d",num[0]);    count=1;    for(;;)    {        num[count]=get_next(num[count-1]);        printf("-> %d",num[count]);        int found=0;        for(int i=0;i<count;i++)            if(num[i]==num[count])        {            found=1;            break;        }        if(found)            break;        count++;    }    printf("\n");    return 0;}