130:被围绕的区域

src/main/java/leetcode/editor/cn/SurroundedRegions.java

@@ -0,0 +1,104 @@
+//给你一个 m x n 的矩阵 board ，由若干字符 'X' 和 'O' ，找到所有被 'X' 围绕的区域，并将这些区域里所有的 'O' 用 'X' 填充
+//。
+// 
+// 
+// 
+//
+// 示例 1： 
+//
+// 
+//输入：board = [["X","X","X","X"],["X","O","O","X"],["X","X","O","X"],["X","O","X"
+//,"X"]]
+//输出：[["X","X","X","X"],["X","X","X","X"],["X","X","X","X"],["X","O","X","X"]]
+//解释：被围绕的区间不会存在于边界上，换句话说，任何边界上的 'O' 都不会被填充为 'X'。 任何不在边界上，或不与边界上的 'O' 相连的 'O' 最终都
+//会被填充为 'X'。如果两个元素在水平或垂直方向相邻，则称它们是“相连”的。
+// 
+//
+// 示例 2： 
+//
+// 
+//输入：board = [["X"]]
+//输出：[["X"]]
+// 
+//
+// 
+//
+// 提示： 
+//
+// 
+// m == board.length 
+// n == board[i].length 
+// 1 <= m, n <= 200 
+// board[i][j] 为 'X' 或 'O' 
+// 
+// 
+// 
+// Related Topics 深度优先搜索 广度优先搜索 并查集 数组 矩阵 
+// 👍 587 👎 0
+
+package leetcode.editor.cn;
+
+import javafx.util.Pair;
+
+import java.util.LinkedList;
+import java.util.Queue;
+
+//130:被围绕的区域
+class SurroundedRegions {
+    public static void main(String[] args) {
+        //测试代码
+        Solution solution = new SurroundedRegions().new Solution();
+    }
+
+    //力扣代码
+    //leetcode submit region begin(Prohibit modification and deletion)
+    class Solution {
+        public void solve(char[][] board) {
+            boolean[][] use = new boolean[board.length][board[0].length];
+            Queue<Pair<Integer, Integer>> queue = new LinkedList<>();
+            for (int i = 0; i < board.length; i++) {
+                if (board[i][0] == 'O') {
+                    queue.add(new Pair<>(i, 0));
+                    use[i][0] = true;
+                }
+                if (board[i][board[0].length - 1] == 'O') {
+                    queue.add(new Pair<>(i, board[0].length - 1));
+                    use[i][board[0].length - 1] = true;
+                }
+            }
+            for (int i = 1; i < board[0].length - 1; i++) {
+                if (board[0][i] == 'O') {
+                    queue.add(new Pair<>(0, i));
+                    use[0][i] = true;
+                }
+                if (board[board.length - 1][i] == 'O') {
+                    queue.add(new Pair<>(board.length - 1, i));
+                    use[board.length - 1][i] = true;
+                }
+            }
+            int[] xIndex = new int[]{-1, 1, 0, 0};
+            int[] yIndex = new int[]{0, 0, -1, 1};
+            while (!queue.isEmpty()) {
+                Pair<Integer, Integer> pair = queue.poll();
+                for (int i = 0; i < 4; i++) {
+                    int x = pair.getKey() + xIndex[i];
+                    int y = pair.getValue() + yIndex[i];
+                    if (x < 0 || x >= board.length || y < 0 || y >= board[0].length || use[x][y] || board[x][y] == 'X') {
+                        continue;
+                    }
+                    queue.add(new Pair<>(x, y));
+                    use[x][y] = true;
+                }
+            }
+            for (int i = 0; i < board.length; i++) {
+                for (int j = 0; j < board[0].length; j++) {
+                    if (board[i][j] == 'O' && !use[i][j]) {
+                        board[i][j] = 'X';
+                    }
+                }
+            }
+        }
+    }
+//leetcode submit region end(Prohibit modification and deletion)
+
+}

src/main/java/leetcode/editor/cn/SurroundedRegions.md

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+给你一个 <code>m x n</code> 的矩阵 <code>board</code> ，由若干字符 <code>'X'</code> 和 <code>'O'</code> ，找到所有被 <code>'X'</code> 围绕的区域，并将这些区域里所有的 <code>'O'</code> 用 <code>'X'</code> 填充。
+<div class="original__bRMd">
+<div>
+<p> </p>
+
+<p><strong>示例 1：</strong></p>
+<img alt="" src="https://assets.leetcode.com/uploads/2021/02/19/xogrid.jpg" style="width: 550px; height: 237px;" />
+<pre>
+<strong>输入：</strong>board = [["X","X","X","X"],["X","O","O","X"],["X","X","O","X"],["X","O","X","X"]]
+<strong>输出：</strong>[["X","X","X","X"],["X","X","X","X"],["X","X","X","X"],["X","O","X","X"]]
+<strong>解释：</strong>被围绕的区间不会存在于边界上，换句话说，任何边界上的 <code>'O'</code> 都不会被填充为 <code>'X'</code>。 任何不在边界上，或不与边界上的 <code>'O'</code> 相连的 <code>'O'</code> 最终都会被填充为 <code>'X'</code>。如果两个元素在水平或垂直方向相邻，则称它们是“相连”的。
+</pre>
+
+<p><strong>示例 2：</strong></p>
+
+<pre>
+<strong>输入：</strong>board = [["X"]]
+<strong>输出：</strong>[["X"]]
+</pre>
+
+<p> </p>
+
+<p><strong>提示：</strong></p>
+
+<ul>
+	<li><code>m == board.length</code></li>
+	<li><code>n == board[i].length</code></li>
+	<li><code>1 <= m, n <= 200</code></li>
+	<li><code>board[i][j]</code> 为 <code>'X'</code> 或 <code>'O'</code></li>
+</ul>
+</div>
+</div>
+<div><div>Related Topics</div><div><li>深度优先搜索</li><li>广度优先搜索</li><li>并查集</li><li>数组</li><li>矩阵</li></div></div>\n<div><li>👍 587</li><li>👎 0</li></div>