题目链接：​​https://www.51nod.com/onlineJudge/questionCode.html#!problemId=2020​​

思路：排序 水水

1 #include<iostream>
 2 #include<algorithm>
 3 #include<string>
 4 #include<cstring>
 5 #include<cmath>
 6 using namespace std;
 7 int a[3];
 8 bool cmp(int x,int y)
 9 {
10     return x>y;
11 }
12 int main()
13 {
14     int t;
15     cin>>t;
16     int n,k;
17     while(t--){
18         cin>>n>>k;
19         int sum1,sum2;
20         while(k--){
21             a[0]=n/1000;
22             a[1]=(n-a[0]*1000)/100;
23             a[2]=(n-a[0]*1000-a[1]*100)/10;
24             a[3]=n%10;
25             sort(a,a+4);
26             sum1=a[3]*1000+a[2]*100+a[1]*10+a[0];
27             sort(a,a+4,cmp);
28             sum2=a[3]*1000+a[2]*100+a[1]*10+a[0];
29             n=abs(sum1-sum2);
30         }
31         cout<<n<<endl;
32     }
33     return 0;
34 }