## 题目描述 给定一个 m x n 二维字符网格 board 和一个单词（字符串）列表 words， 返回所有二维网格上的单词 。 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在一个单词中不允许被重复使用。 ## 示例 **示例 1:** **输入:** board = [["o","a","a","n"],["e","t","a","e"],["i","h","k","r"],["i","f","l","v"]], words = ["oath","pea","eat","rain"] **输出:** ["eat","oath"] **示例 2:** **输入:** board = [["a","b"],["c","d"]], words = ["abcb"] **输出:** [] ## 约束条件 m == board.length n == board[i].length 1 <= m, n <= 12 board[i][j] 是一个小写英文字母 1 <= words.length <= 3 * 104 1 <= words[i].length <= 10 words[i] 由小写英文字母组成 words 中的所有字符串互不相同 ## LeetCode 链接 https://leetcode.cn/problems/word-search-ii/