X mod f(x) 数论

Question

Problem Description
Here is a function f(x):
　　　int f ( int x ) {
　　　 if ( x == 0 ) return 0;
　　　 return f ( x / 10 ) + x % 10;
　　　}

　　　Now, you want to know, in a given interval A, B, how many integer x that mod f(x) equal to 0.

Input
　　　The first line has an integer T (1 <= T <= 50), indicate the number of test cases.
　　　Each test case has two integers A, B.

Output
　　　For each test case, output only one line containing the case number and an integer indicated the number of x.

SampleInput
2
1 10
11 20

SampleOutput
Case 1: 10
Case 2: 3

Answer 1

http://blog.csdn.net/hnust_xiehonghao/article/details/7895547