# 单词搜索

<p>给定一个 <code>m x n</code> 二维字符网格 <code>board</code> 和一个字符串单词 <code>word</code> 。如果 <code>word</code> 存在于网格中，返回 <code>true</code> ；否则，返回 <code>false</code> 。</p><p>单词必须按照字母顺序，通过相邻的单元格内的字母构成，其中“相邻”单元格是那些水平相邻或垂直相邻的单元格。同一个单元格内的字母不允许被重复使用。</p><p> </p><p><strong>示例 1：</strong></p><img alt="" src="https://img-service.csdnimg.cn/img_convert/d41f067a92645388770d389f5e4d7269.jpeg" style="width: 322px; height: 242px;" /><pre><strong>输入：</strong>board = [["A","B","C","E"],["S","F","C","S"],["A","D","E","E"]], word = "ABCCED"<strong><br />输出：</strong>true</pre><p><strong>示例 2：</strong></p><img alt="" src="https://img-service.csdnimg.cn/img_convert/56b7681c631f1e73b77fe9a7475033ea.jpeg" style="width: 322px; height: 242px;" /><pre><strong>输入：</strong>board = [["A","B","C","E"],["S","F","C","S"],["A","D","E","E"]], word = "SEE"<strong><br />输出：</strong>true</pre><p><strong>示例 3：</strong></p><img alt="" src="https://img-service.csdnimg.cn/img_convert/58c1e99e8c54dfb7496d44f2d05c8e96.jpeg" style="width: 322px; height: 242px;" /><pre><strong>输入：</strong>board = [["A","B","C","E"],["S","F","C","S"],["A","D","E","E"]], word = "ABCB"<strong><br />输出：</strong>false</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 <= 6</code></li>	<li><code>1 <= word.length <= 15</code></li>	<li><code>board</code> 和 <code>word</code> 仅由大小写英文字母组成</li></ul><p> </p><p><strong>进阶：</strong>你可以使用搜索剪枝的技术来优化解决方案，使其在 <code>board</code> 更大的情况下可以更快解决问题？</p>

## template

```java
class Solution {
	public boolean exist(char[][] board, String word) {
		int cl = board.length;
		int rl = board[0].length;
		boolean[][] flag = new boolean[cl][rl];
		for (int i = 0; i < cl; i++) {
			for (int j = 0; j < rl; j++) {
				if (find(board, word, flag, i, j, 0))
					return true;
			}
		}

		return false;
	}

	public boolean find(char[][] board, String word, boolean[][] flag, int i, int j, int index) {
		int cl = board.length;
		int rl = board[0].length;
		if (word.length() == index)
			return true;
		if (i < 0 || i >= cl || j >= rl || j < 0)
			return false;
		if (flag[i][j] || word.charAt(index) != board[i][j])
			return false;
		flag[i][j] = true;
		boolean judge = find(board, word, flag, i - 1, j, index + 1) || find(board, word, flag, i + 1, j, index + 1)
				|| find(board, word, flag, i, j - 1, index + 1) || find(board, word, flag, i, j + 1, index + 1);
		flag[i][j] = false;
		return judge;

	}
}

```

## 答案

```java

```

## 选项

### A

```java

```

### B

```java

```

### C

```java

```