136 lines
3.8 KiB
Java
136 lines
3.8 KiB
Java
//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 。
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//
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// 实现词典类 WordDictionary ：
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//
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//
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// WordDictionary() 初始化词典对象
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// void addWord(word) 将 word 添加到数据结构中，之后可以对它进行匹配
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// 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
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//'.' ，每个 . 都可以表示任何一个字母。
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//
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//
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//
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//
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// 示例：
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//
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//
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//输入：
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//["WordDictionary","addWord","addWord","addWord","search","search","search",
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//"search"]
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//[[],["bad"],["dad"],["mad"],["pad"],["bad"],[".ad"],["b.."]]
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//输出：
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//[null,null,null,null,false,true,true,true]
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//
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//解释：
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//WordDictionary wordDictionary = new WordDictionary();
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//wordDictionary.addWord("bad");
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//wordDictionary.addWord("dad");
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//wordDictionary.addWord("mad");
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//wordDictionary.search("pad"); // return False
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//wordDictionary.search("bad"); // return True
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//wordDictionary.search(".ad"); // return True
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//wordDictionary.search("b.."); // return True
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//
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//
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//
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//
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// 提示：
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//
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//
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// 1 <= word.length <= 500
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// addWord 中的 word 由小写英文字母组成
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// search 中的 word 由 '.' 或小写英文字母组成
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// 最多调用 50000 次 addWord 和 search
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//
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// Related Topics 深度优先搜索 设计 字典树 字符串 👍 328 👎 0
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package leetcode.editor.cn;
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//211:添加与搜索单词 - 数据结构设计
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class DesignAddAndSearchWordsDataStructure {
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public static void main(String[] args) {
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//测试代码
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// Solution solution = new DesignAddAndSearchWordsDataStructure().new Solution();
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}
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//力扣代码
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//leetcode submit region begin(Prohibit modification and deletion)
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class WordDictionary {
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private Trie root;
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public WordDictionary() {
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root = new Trie();
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}
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public void addWord(String word) {
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root.insert(word);
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}
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public boolean search(String word) {
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return dfs(word, 0, root);
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}
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private boolean dfs(String word, int index, Trie node) {
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if (index == word.length()) {
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return node.isEnd();
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}
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char ch = word.charAt(index);
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if (Character.isLetter(ch)) {
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int childIndex = ch - 'a';
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Trie child = node.getChildren()[childIndex];
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if (child != null && dfs(word, index + 1, child)) {
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return true;
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}
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} else {
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for (int i = 0; i < 26; i++) {
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Trie child = node.getChildren()[i];
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if (child != null && dfs(word, index + 1, child)) {
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return true;
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}
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}
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}
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return false;
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}
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}
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class Trie {
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private Trie[] children;
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private boolean isEnd;
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public Trie() {
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children = new Trie[26];
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isEnd = false;
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}
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public void insert(String word) {
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Trie node = this;
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for (int i = 0; i < word.length(); i++) {
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char ch = word.charAt(i);
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int index = ch - 'a';
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if (node.children[index] == null) {
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node.children[index] = new Trie();
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}
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node = node.children[index];
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}
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node.isEnd = true;
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}
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public Trie[] getChildren() {
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return children;
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}
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public boolean isEnd() {
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return isEnd;
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}
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}
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/**
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* Your WordDictionary object will be instantiated and called as such:
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* WordDictionary obj = new WordDictionary();
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* obj.addWord(word);
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* boolean param_2 = obj.search(word);
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*/
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//leetcode submit region end(Prohibit modification and deletion)
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} |