PawnsAndKings | Topcoder Archive

Problem Statement

You are given a String[] board representing a standard 8x8 chess board. The '.' character represents an empty cell, 'P' represents a cell occupied by a pawn, and 'K' represents a cell occupied by a king.

In a single move, a king can move to any of its 8 neighboring cells. If you move a king into a cell occupied by a pawn, the king will capture that pawn. You can never move a king outside the board or into a cell already occupied by another king.

Return the minimal number of moves required for the kings to capture all the pawns.

Definition

Class:: PawnsAndKings
Method:: minNumberOfMoves
Parameters:: String[]
Returns:: int
Method signature:: int minNumberOfMoves(String[] board)
(be sure your method is public)

Constraints

board will contain exactly 8 elements.
Each element of board will contain exactly 8 characters.
Each character of each element of board will be '.', or an uppercase 'P', or an uppercase 'K'.
The number of 'P' characters will be between 1 and 10, inclusive.
The number of 'K' characters will be between 1 and 10, inclusive.

Examples

```
{".PPPPKP.", 
 "........", 
 "........", 
 "........", 
 "........", 
 "........", 
 "........", 
 "........"}
```
```
Returns: 6
```
The only king will make the minimal number of moves by first capturing the only pawn at its right side and then capturing the other pawns.
```
{"P......P", 
 "........", 
 "........",
 "........",
 "...KK...",
 "........",
 "........",
 "P......P"}
```
```
Returns: 20
```
If we mark the kings with A and B and the pawns with 1, 2, 3 and 4, then one possible solution is that A captures the pawns 1 and 2, and B captures the pawns 3 and 4. 1......4 ........ ........ ........ ...AB... ........ ........ 2......3

{".....P.P",
 "..K....P",
 "....K...",
 "..PP...P",
 "...K..KK",
 "........",
 "K.......",
 "KP.K...."}

Returns: 9

{"PK...KPK",
 "......K.",
 "...K....",
 "..KPK...",
 "...K....",
 "........",
 "........",
 "K..P.K.P"}

Returns: 8

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