MinimalDifference | Topcoder Archive

Problem Statement

The digit sum of an integer is the sum of its digits in decimal notation. For example, the digit sum of 1234 is 1+2+3+4=10, and the digit sum of 3443 is 3+4+4+3=14.
You are given three integers: A, B and C. Return the integer X between A and B, inclusive, such that the absolute difference between the digit sum of X and the digit sum of C is as small as possible. If there are multiple possible values for X, return the smallest among them.

Definition

Class:: MinimalDifference
Method:: findNumber
Parameters:: int, int, int
Returns:: int
Method signature:: int findNumber(int A, int B, int C)
(be sure your method is public)

Constraints

A, B and C will each be between 1 and 1,000,000,000, inclusive.
B-A will be between 0 and 100,000, inclusive.

Examples

```
1
```
```
9
```
```
10
```
```
Returns: 1
```
The digit sum of C is 1+0=1. Of the integers between 1 and 9, inclusive, only 1 has a digit sum equal to 1.
```
11
```
```
20
```
```
20
```
```
Returns: 11
```
The digit sum of C is 2+0=2. Of the integers between 11 and 20, inclusive, there are two which also have a digit sum of 2: 11 (1+1=2) and 20 (2+0=2). We choose 11 because it is smaller than 20.
```
1
```
```
1
```
```
999
```
```
Returns: 1
```
```
100
```
```
1000
```
```
99
```
```
Returns: 189
```
```
1987
```
```
9123
```
```
1
```
```
Returns: 2000
```

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