211:添加与搜索单词 - 数据结构设计(官方)

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huangge1199 2021-10-19 14:46:47 +08:00
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commit 66c2b94686
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//请你设计一个数据结构支持 添加新单词 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) 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
//
//
//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
//
//
//
//
// 提示
//
//
// 1 <= word.length <= 500
// addWord 中的 word 由小写英文字母组成
// search 中的 word '.' 或小写英文字母组成
// 最多调用 50000 addWord search
//
// Related Topics 深度优先搜索 设计 字典树 字符串 👍 328 👎 0
package leetcode.editor.cn;
//211:添加与搜索单词 - 数据结构设计
class DesignAddAndSearchWordsDataStructure {
public static void main(String[] args) {
//测试代码
// Solution solution = new DesignAddAndSearchWordsDataStructure().new Solution();
}
//力扣代码
//leetcode submit region begin(Prohibit modification and deletion)
class WordDictionary {
private Trie root;
public WordDictionary() {
root = new Trie();
}
public void addWord(String word) {
root.insert(word);
}
public boolean search(String word) {
return dfs(word, 0, root);
}
private boolean dfs(String word, int index, Trie node) {
if (index == word.length()) {
return node.isEnd();
}
char ch = word.charAt(index);
if (Character.isLetter(ch)) {
int childIndex = ch - 'a';
Trie child = node.getChildren()[childIndex];
if (child != null && dfs(word, index + 1, child)) {
return true;
}
} else {
for (int i = 0; i < 26; i++) {
Trie child = node.getChildren()[i];
if (child != null && dfs(word, index + 1, child)) {
return true;
}
}
}
return false;
}
}
class Trie {
private Trie[] children;
private boolean isEnd;
public Trie() {
children = new Trie[26];
isEnd = false;
}
public void insert(String word) {
Trie node = this;
for (int i = 0; i < word.length(); i++) {
char ch = word.charAt(i);
int index = ch - 'a';
if (node.children[index] == null) {
node.children[index] = new Trie();
}
node = node.children[index];
}
node.isEnd = true;
}
public Trie[] getChildren() {
return children;
}
public boolean isEnd() {
return isEnd;
}
}
/**
* Your WordDictionary object will be instantiated and called as such:
* WordDictionary obj = new WordDictionary();
* obj.addWord(word);
* boolean param_2 = obj.search(word);
*/
//leetcode submit region end(Prohibit modification and deletion)
}

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<p>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 。</p>
<p>实现词典类 <code>WordDictionary</code> </p>
<ul>
<li><code>WordDictionary()</code> 初始化词典对象</li>
<li><code>void addWord(word)</code><code>word</code> 添加到数据结构中,之后可以对它进行匹配</li>
<li><code>bool search(word)</code> 如果数据结构中存在字符串与 <code>word</code> 匹配,则返回 <code>true</code> ;否则,返回  <code>false</code><code>word</code> 中可能包含一些 <code>'.'</code> ,每个 <code>.</code> 都可以表示任何一个字母。</li>
</ul>
<p> </p>
<p><strong>示例:</strong></p>
<pre>
<strong>输入:</strong>
["WordDictionary","addWord","addWord","addWord","search","search","search","search"]
[[],["bad"],["dad"],["mad"],["pad"],["bad"],[".ad"],["b.."]]
<strong>输出:</strong>
[null,null,null,null,false,true,true,true]
<strong>解释:</strong>
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
</pre>
<p> </p>
<p><strong>提示:</strong></p>
<ul>
<li><code>1 <= word.length <= 500</code></li>
<li><code>addWord</code> 中的 <code>word</code> 由小写英文字母组成</li>
<li><code>search</code> 中的 <code>word</code> 由 '.' 或小写英文字母组成</li>
<li>最多调用 <code>50000</code><code>addWord</code><code>search</code></li>
</ul>
<div><div>Related Topics</div><div><li>深度优先搜索</li><li>设计</li><li>字典树</li><li>字符串</li></div></div><br><div><li>👍 328</li><li>👎 0</li></div>