diff --git a/src/main/java/leetcode/editor/cn/WordSearch.java b/src/main/java/leetcode/editor/cn/WordSearch.java new file mode 100644 index 0000000..cb89360 --- /dev/null +++ b/src/main/java/leetcode/editor/cn/WordSearch.java @@ -0,0 +1,119 @@ +//给定一个 m x n 二维字符网格 board 和一个字符串单词 word 。如果 word 存在于网格中，返回 true ；否则，返回 false 。 +// +// 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。 +// +// +// +// 示例 1： +// +// +//输入：board = [["A","B","C","E"],["S","F","C","S"],["A","D","E","E"]], word = "AB +//CCED" +//输出：true +// +// +// 示例 2： +// +// +//输入：board = [["A","B","C","E"],["S","F","C","S"],["A","D","E","E"]], word = "SE +//E" +//输出：true +// +// +// 示例 3： +// +// +//输入：board = [["A","B","C","E"],["S","F","C","S"],["A","D","E","E"]], word = "AB +//CB" +//输出：false +// +// +// +// +// 提示： +// +// +// m == board.length +// n = board[i].length +// 1 <= m, n <= 6 +// 1 <= word.length <= 15 +// board 和 word 仅由大小写英文字母组成 +// +// +// +// +// 进阶：你可以使用搜索剪枝的技术来优化解决方案，使其在 board 更大的情况下可以更快解决问题？ +// Related Topics 数组 回溯 矩阵 +// 👍 973 👎 0 + +package leetcode.editor.cn; + +import java.util.Arrays; + +//79:单词搜索 +public class WordSearch{ + public static void main(String[] args) { + //测试代码 + Solution solution = new WordSearch().new Solution(); + } + //力扣代码 + //leetcode submit region begin(Prohibit modification and deletion) +class Solution { + public boolean exist(char[][] board, String word) { + + String str = Arrays.deepToString(board); + for (int i = 0; i < word.length(); i++) { + if (str.indexOf(word.charAt(i)) == -1) { + return false; + } + } + + for (int i = 0; i < board.length; i++) { + for (int j = 0; j < board[0].length; j++) { + if (board[i][j] == word.charAt(0)) { + if (dfs(board, word, i, j, 0, new int[board.length][board[0].length])) { + return true; + } + } + } + } + + return false; + } + + /** + * 深度优先搜索 + * @param board 传入的二维字符网格 + * @param word 目标字符串 + * @param i 起点 i 坐标 + * @param j 起点 j 坐标 + * @param index 遍历到word的哪一个位置了 + * @param visit 访问数组，记录哪些地方已经走过 + * @return + */ + private boolean dfs(char[][] board, String word, int i, int j, int index, int[][] visit) { + + if (i < 0 || i >= board.length || j < 0 || j >= board[0].length + || board[i][j] != word.charAt(index) || visit[i][j] == 1) { + return false; + } + if (index == word.length() - 1) { + return true; + } + visit[i][j] = 1; + int[][] direction = new int[][]{{i - 1, j}, {i + 1, j}, {i, j - 1}, {i, j + 1}}; + for (int[] d : direction) { + int[][] copy = new int[visit.length][visit[0].length]; + for (int k = 0; k < visit.length; k++) { + copy[k] = Arrays.copyOf(visit[k], visit[0].length); + } + if (dfs(board, word, d[0], d[1], index + 1, copy)) { + return true; + } + } + return false; + } +} +//leetcode submit region end(Prohibit modification and deletion) + +} \ No newline at end of file diff --git a/src/main/java/leetcode/editor/cn/WordSearch.md b/src/main/java/leetcode/editor/cn/WordSearch.md new file mode 100644 index 0000000..0e5a623 --- /dev/null +++ b/src/main/java/leetcode/editor/cn/WordSearch.md @@ -0,0 +1,43 @@ +

给定一个 m x n 二维字符网格 board 和一个字符串单词 word 。如果 word 存在于网格中，返回 true ；否则，返回 false 。

+ +

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。

+ +

 

+ +

示例 1：

+ +
+输入：board = [["A","B","C","E"],["S","F","C","S"],["A","D","E","E"]], word = "ABCCED"
+输出：true
+
+ +

示例 2：

+ +
+输入：board = [["A","B","C","E"],["S","F","C","S"],["A","D","E","E"]], word = "SEE"
+输出：true
+
+ +

示例 3：

+ +
+输入：board = [["A","B","C","E"],["S","F","C","S"],["A","D","E","E"]], word = "ABCB"
+输出：false
+
+ +

 

+ +

提示：

+ + + +

 

+ +

进阶：你可以使用搜索剪枝的技术来优化解决方案，使其在 board 更大的情况下可以更快解决问题？

+
Related Topics
  • 数组
  • 回溯
  • 矩阵
    • \n
  • 👍 973
  • 👎 0
    • \ No newline at end of file