Add solution #529

Author: JoshCrozier

README.md

@@ -424,6 +424,7 @@
 525|[Contiguous Array](./0525-contiguous-array.js)|Medium|
 526|[Beautiful Arrangement](./0526-beautiful-arrangement.js)|Medium|
 528|[Random Pick with Weight](./0528-random-pick-with-weight.js)|Medium|
+529|[Minesweeper](./0529-minesweeper.js)|Medium|
 530|[Minimum Absolute Difference in BST](./0530-minimum-absolute-difference-in-bst.js)|Easy|
 541|[Reverse String II](./0541-reverse-string-ii.js)|Easy|
 542|[01 Matrix](./0542-01-matrix.js)|Medium|

solutions/0529-minesweeper.js

@@ -0,0 +1,68 @@
+/**
+ * 529. Minesweeper
+ * https://leetcode.com/problems/minesweeper/
+ * Difficulty: Medium
+ *
+ * Let's play the minesweeper game (Wikipedia, online game)!
+ *
+ * You are given an m x n char matrix board representing the game board where:
+ * - 'M' represents an unrevealed mine,
+ * - 'E' represents an unrevealed empty square,
+ * - 'B' represents a revealed blank square that has no adjacent mines (i.e., above, below,
+ *   left, right, and all 4 diagonals),
+ * - digit ('1' to '8') represents how many mines are adjacent to this revealed square, and
+ * - 'X' represents a revealed mine.
+ *
+ * You are also given an integer array click where click = [clickr, clickc] represents the
+ * next click position among all the unrevealed squares ('M' or 'E').
+ *
+ * Return the board after revealing this position according to the following rules:
+ * 1. If a mine 'M' is revealed, then the game is over. You should change it to 'X'.
+ * 2. If an empty square 'E' with no adjacent mines is revealed, then change it to a revealed
+ *    blank 'B' and all of its adjacent unrevealed squares should be revealed recursively.
+ * 3. If an empty square 'E' with at least one adjacent mine is revealed, then change it to a
+ *    digit ('1' to '8') representing the number of adjacent mines.
+ * 4. Return the board when no more squares will be revealed.
+ */
+
+/**
+ * @param {character[][]} board
+ * @param {number[]} click
+ * @return {character[][]}
+ */
+var updateBoard = function(board, click) {
+  const [row, col] = click;
+  const rows = board.length;
+  const cols = board[0].length;
+  const directions = [
+    [-1, -1], [-1, 0], [-1, 1], [0, -1], [0, 1], [1, -1], [1, 0], [1, 1]
+  ];
+
+  if (board[row][col] === 'M') {
+    board[row][col] = 'X';
+    return board;
+  }
+
+  dfs(row, col);
+  return board;
+
+  function dfs(r, c) {
+    if (r < 0 || r >= rows || c < 0 || c >= cols || board[r][c] !== 'E') return;
+
+    let mines = 0;
+    for (const [dr, dc] of directions) {
+      const nr = r + dr;
+      const nc = c + dc;
+      if (nr >= 0 && nr < rows && nc >= 0 && nc < cols && board[nr][nc] === 'M') {
+        mines++;
+      }
+    }
+
+    board[r][c] = mines > 0 ? mines.toString() : 'B';
+    if (mines === 0) {
+      for (const [dr, dc] of directions) {
+        dfs(r + dr, c + dc);
+      }
+    }
+  }
+};