TheSwap | Topcoder Archive

Problem Statement

There is nothing more beautiful than just an integer number.

You are given an integer n. Write down n in decimal notation with no leading zeroes, and let M be the number of written digits. Perform the following operation exactly k times:

Choose two different 1-based positions, i and j, such that 1 &lt= i &lt j &lt= M. Swap the digits at positions i and j. This swap must not cause the resulting number to have a leading zero, i.e., if the digit at position j is zero, then i must be strictly greater than 1.

Return the maximal possible number you can get at the end of this procedure. If it's not possible to perform k operations, return -1 instead.

Definition

Class:: TheSwap
Method:: findMax
Parameters:: int, int
Returns:: int
Method signature:: int findMax(int n, int k)
(be sure your method is public)

Constraints

n will be between 1 and 1,000,000, inclusive.
k will be between 1 and 10, inclusive.

Examples

```
16375
```
```
1
```
```
Returns: 76315
```
The optimal way is to swap 1 and 7.
```
432
```
```
1
```
```
Returns: 423
```
In this case the result is less than the given number.
```
90
```
```
4
```
```
Returns: -1
```
We can't make even a single operation because it would cause the resulting number to have a leading zero.
```
5
```
```
2
```
```
Returns: -1
```
Here we can't choose two different positions for an operation.
```
436659
```
```
2
```
```
Returns: 966354
```

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