Add solution #999

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,077 LeetCode solutions in JavaScript
+# 1,078 LeetCode solutions in JavaScript
 
 [https://leetcode.com/](https://leetcode.com/)
 
@@ -807,6 +807,7 @@
 996|[Number of Squareful Arrays](./solutions/0996-number-of-squareful-arrays.js)|Hard|
 997|[Find the Town Judge](./solutions/0997-find-the-town-judge.js)|Easy|
 998|[Maximum Binary Tree II](./solutions/0998-maximum-binary-tree-ii.js)|Medium|
+999|[Available Captures for Rook](./solutions/0999-available-captures-for-rook.js)|Easy|
 1002|[Find Common Characters](./solutions/1002-find-common-characters.js)|Easy|
 1004|[Max Consecutive Ones III](./solutions/1004-max-consecutive-ones-iii.js)|Medium|
 1005|[Maximize Sum Of Array After K Negations](./solutions/1005-maximize-sum-of-array-after-k-negations.js)|Easy|

solutions/0999-available-captures-for-rook.js

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+/**
+ * 999. Available Captures for Rook
+ * https://leetcode.com/problems/available-captures-for-rook/
+ * Difficulty: Easy
+ *
+ * You are given an 8 x 8 matrix representing a chessboard. There is exactly one white rook
+ * represented by 'R', some number of white bishops 'B', and some number of black pawns 'p'.
+ * Empty squares are represented by '.'.
+ *
+ * A rook can move any number of squares horizontally or vertically (up, down, left, right)
+ * until it reaches another piece or the edge of the board. A rook is attacking a pawn if it
+ * can move to the pawn's square in one move.
+ *
+ * Note: A rook cannot move through other pieces, such as bishops or pawns. This means a rook
+ * cannot attack a pawn if there is another piece blocking the path.
+ *
+ * Return the number of pawns the white rook is attacking.
+ */
+
+/**
+ * @param {character[][]} board
+ * @return {number}
+ */
+var numRookCaptures = function(board) {
+  let rookRow;
+  let rookCol;
+
+  for (let i = 0; i < 8; i++) {
+    for (let j = 0; j < 8; j++) {
+      if (board[i][j] === 'R') {
+        rookRow = i;
+        rookCol = j;
+        break;
+      }
+    }
+  }
+
+  const result = countPawns(-1, 0) + countPawns(1, 0)
+    + countPawns(0, -1) + countPawns(0, 1);
+
+  return result;
+
+  function countPawns(rowStep, colStep) {
+    let row = rookRow + rowStep;
+    let col = rookCol + colStep;
+
+    while (row >= 0 && row < 8 && col >= 0 && col < 8) {
+      if (board[row][col] === 'p') return 1;
+      if (board[row][col] === 'B') return 0;
+      row += rowStep;
+      col += colStep;
+    }
+    return 0;
+  }
+};