leetcode 211题 添加与搜索单词 - 数据结构设计
请你设计一个数据结构，支持 添加新单词 和 查找字符串是否与任何先前添加的字符串匹配 。
实现词典类 WordDictionary ：
WordDictionary() 初始化词典对象 void addWord(word) 将 word 添加到数据结构中，之后可以对它进行匹配 bool search(word) 如果数据结构中存在字符串与 word 匹配，则返回 true ；否则，返回 false 。word 中可能包含一些 ‘.’ ，每个 . 都可以表示任何一个字母。
示例 1：
输入：
["WordDictionary","addWord","addWord","addWord","search","search","search","search"]
[[],["bad"],["dad"],["mad"],["pad"],["bad"],[".ad"],["b.."]]
输出：
[null,null,null,null,false,true,true,true]
解释：
WordDictionary wordDictionary = new WordDictionary();
wordDictionary.addWord("bad");
wordDictionary.addWord("dad");
wordDictionary.addWord("mad");
wordDictionary.search("pad"); // return False
wordDictionary.search("bad"); // return True
wordDictionary.search(".ad"); // return True
wordDictionary.search("b.."); // return True
思路
bfs
代码
var WordDictionary = function() {
this.parent = {};
};
/**
* @param {string} word
* @return {void}
*/
WordDictionary.prototype.addWord = function(word) {
let curr = this.parent;
for (const w of word) {
if (curr[w]) {
curr = curr[w];
} else {
curr[w] = {};
curr = curr[w];
}
}
curr.isWord = true;
};
/**
* @param {string} word
* @return {boolean}
*/
WordDictionary.prototype.search = function(word, parent = this.parent) {
let curr = parent;
for (let i=0; i<word.length; i++) {
const w = word[i];
if (w === '.') {
let isMatched = false;
for (const key in curr) {
if (this.search(word.slice(i+1), curr[key])) {
isMatched = true;
}
}
return isMatched;
} else if (!curr[w]) {
return false;
}
curr = curr[w];
}
return !!curr.isWord;
};
/**
* Your WordDictionary object will be instantiated and called as such:
* var obj = new WordDictionary()
* obj.addWord(word)
* var param_2 = obj.search(word)
*/
复杂度分析
- 时间复杂度：O(N)
- 空间复杂度：O(N)