solves rook captures

Author: anishLearnsToCode

README.md

@@ -268,7 +268,7 @@
 | 989 | [Add to Array Form of Integer](https://leetcode.com/problems/add-to-array-form-of-integer) | [![Java](assets/java.png)](src/AddToArrayFormOfInteger.java) |
 | 993 | [Cousins in Binary Tree](https://leetcode.com/problems/cousins-in-binary-tree) | [![Java](assets/java.png)](src/CousinsInBinaryTree.java) |
 | 997 | [Find the Town Judge](https://leetcode.com/problems/find-the-town-judge) | [![Java](assets/java.png)](src/FindTheTownJudge.java) |
-| 999 | [Available Captures for Rook](https://leetcode.com/problems/available-captures-for-rook) | |
+| 999 | [Available Captures for Rook](https://leetcode.com/problems/available-captures-for-rook) | [![Java](assets/java.png)](src/AvailableCapturesForRook.java) |
 | 1002 | [Find Common Characters](https://leetcode.com/problems/find-common-characters) | |
 | 1005 | [Maximize Sum of Array After K Negations](https://leetcode.com/problems/maximize-sum-of-array-after-k-negations) | |
 | 1009 | [Complement of Base 10 Integer](https://leetcode.com/problems/complement-of-base-10-integer) | [![Java](https://img.icons8.com/color/40/000000/java-coffee-cup-logo.png)](src/NumberComplement.java) |

src/AvailableCapturesForRook.java

@@ -0,0 +1,64 @@
+public class AvailableCapturesForRook {
+    private static final class Position {
+        private final int row;
+        private final int column;
+
+        private Position(int row, int column) {
+            this.row = row;
+            this.column = column;
+        }
+    }
+
+    private static final char ROOK = 'R';
+    private static final char BISHOP = 'B';
+    private static final char PAWN = 'p';
+
+    public int numRookCaptures(char[][] board) {
+        Position rookPosition = getPosition(board, ROOK);
+        return (canCapturePawnInNorth(board, rookPosition) ? 1 : 0) +
+                (canCapturePawnInWest(board, rookPosition) ? 1 : 0) +
+                (canCapturePawnInSouth(board, rookPosition) ? 1 : 0) +
+                (canCapturePawnInEast(board, rookPosition) ? 1 : 0);
+    }
+
+    private Position getPosition(char[][] board, char piece) {
+        for (int row = 0 ; row < board.length ; row++) {
+            for (int column = 0 ; column < board[0].length ; column++) {
+                if (board[row][column] == piece) return new Position(row, column);
+            }
+        }
+        return null;
+    }
+
+    private boolean canCapturePawnInNorth(char[][] board, Position rookPosition) {
+        for (int row = rookPosition.row - 1 ; row >= 0 ; row--) {
+            if (board[row][rookPosition.column] == BISHOP) return false;
+            if (board[row][rookPosition.column] == PAWN) return true;
+        }
+        return false;
+    }
+
+    private boolean canCapturePawnInSouth(char[][] board, Position rookPosition) {
+        for (int row = rookPosition.row + 1 ; row < board.length ; row++) {
+            if (board[row][rookPosition.column] == BISHOP) return false;
+            if (board[row][rookPosition.column] == PAWN) return true;
+        }
+        return false;
+    }
+
+    private boolean canCapturePawnInWest(char[][] board, Position rookPosition) {
+        for (int column = rookPosition.column + 1 ; column < board[0].length ; column++) {
+            if (board[rookPosition.row][column] == BISHOP) return false;
+            if (board[rookPosition.row][column] == PAWN) return true;
+        }
+        return false;
+    }
+
+    private boolean canCapturePawnInEast(char[][] board, Position rookPosition) {
+        for (int column = rookPosition.column - 1 ; column >= 0 ; column--) {
+            if (board[rookPosition.row][column] == BISHOP) return false;
+            if (board[rookPosition.row][column] == PAWN) return true;
+        }
+        return false;
+    }
+}