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ReplaceWords.java
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ReplaceWords.java
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package com.hncboy;
import java.util.Arrays;
import java.util.List;
/**
* @author hncboy
* @date 2021/12/11 16:20
* @description 648.单词替换
*
* 在英语中,我们有一个叫做 词根(root)的概念,它可以跟着其他一些词组成另一个较长的单词——我们称这个词为 继承词(successor)。
* 例如,词根an,跟随着单词 other(其他),可以形成新的单词 another(另一个)。
* 现在,给定一个由许多词根组成的词典和一个句子。你需要将句子中的所有继承词用词根替换掉。
* 如果继承词有许多可以形成它的词根,则用最短的词根替换它。
* 你需要输出替换之后的句子。
*
* 示例 1:
* 输入:dictionary = ["cat","bat","rat"], sentence = "the cattle was rattled by the battery"
* 输出:"the cat was rat by the bat"
*
* 示例 2:
* 输入:dictionary = ["a","b","c"], sentence = "aadsfasf absbs bbab cadsfafs"
* 输出:"a a b c"
*
* 示例 3:
* 输入:dictionary = ["a", "aa", "aaa", "aaaa"], sentence = "a aa a aaaa aaa aaa aaa aaaaaa bbb baba ababa"
* 输出:"a a a a a a a a bbb baba a"
*
* 示例 4:
* 输入:dictionary = ["catt","cat","bat","rat"], sentence = "the cattle was rattled by the battery"
* 输出:"the cat was rat by the bat"
*
* 示例 5:
* 输入:dictionary = ["ac","ab"], sentence = "it is abnormal that this solution is accepted"
* 输出:"it is ab that this solution is ac"
*
* 提示:
* 1 <= dictionary.length <= 1000
* 1 <= dictionary[i].length <= 100
* dictionary[i] 仅由小写字母组成。
* 1 <= sentence.length <= 10^6
* sentence 仅由小写字母和空格组成。
* sentence 中单词的总量在范围 [1, 1000] 内。
* sentence 中每个单词的长度在范围 [1, 1000] 内。
* sentence 中单词之间由一个空格隔开。
* sentence 没有前导或尾随空格。
* 通过次数 22,965 提交次数 39,013
*
* 来源:力扣(LeetCode)
* 链接:https://leetcode-cn.com/problems/replace-words
* 著作权归领扣网络所有。商业转载请联系官方授权,非商业转载请注明出处。
*/
public class ReplaceWords {
public static void main(String[] args) {
ReplaceWords r = new ReplaceWords();
System.out.println(r.replaceWords(Arrays.asList("cat", "bat", "rat"), "the cattle was rattled by the battery"));
}
public String replaceWords(List<String> dictionary, String sentence) {
// 构建字典树
TrieNode trie = buildTrieTree(dictionary);
StringBuilder result = new StringBuilder();
// 遍历所有单词
for (String word: sentence.split("\\s+")) {
if (result.length() > 0) {
result.append(" ");
}
TrieNode curr = trie;
// 遍历所有字母
for (char letter: word.toCharArray()) {
// 如果字母构不成前缀树或者已经构成了一个前缀树
if (curr.children[letter - 'a'] == null || curr.word != null) {
break;
}
curr = curr.children[letter - 'a'];
}
result.append(curr.word != null ? curr.word : word);
}
return result.toString();
}
/**
* 构建字典树
*
* @param dictionary 词根
* @return 字典树
*/
private TrieNode buildTrieTree(List<String> dictionary) {
TrieNode trie = new TrieNode();
// 遍历所有词根
for (String root : dictionary) {
TrieNode curr = trie;
// 遍历词根的所有字母
for (char letter : root.toCharArray()) {
if (curr.children[letter - 'a'] == null) {
curr.children[letter - 'a'] = new TrieNode();
}
curr = curr.children[letter - 'a'];
}
// 最后一个节点存放词根
curr.word = root;
}
return trie;
}
private static class TrieNode {
String word;
TrieNode[] children = new TrieNode[26];
}
}