648. Replace Words

In English, we have a concept called root, which can be followed by some other words to form another longer word - let's call this word successor. For example, the root an, followed by other, which can form another word another.

Now, given a dictionary consisting of many roots and a sentence. You need to replace all the successor in the sentence with the rootforming it. If a successor has many roots can form it, replace it with the root with the shortest length.

You need to output the sentence after the replacement.

Example 1:

Input: dict = ["cat", "bat", "rat"]sentence = "the cattle was rattled by the battery"Output: "the cat was rat by the bat"

Note:

1. The input will only have lower-case letters.
2. 1 <= dict words number <= 1000
3. 1 <= sentence words number <= 1000
4. 1 <= root length <= 100
5. 1 <= sentence words length <= 1000

Trie树，没什么说的

package l648;import java.util.List;public class Solution {class Trie {boolean end = false;Trie[] next = new Trie[26];}    public String replaceWords(List<String> dict, String sentence) {    Trie root = new Trie();        for(String s : dict) {        buildTrie(root, s);        }                String[] ss = sentence.split(" ");        StringBuilder sb = new StringBuilder();        for(String s : ss) {        StringBuilder t = new StringBuilder();        findPrefix(root, s, t);        sb.append(t).append(" ");        }                return sb.toString().trim();    }private void findPrefix(Trie root, String s, StringBuilder sb) {if(root.end)return ;if("".equals(s))return;char c = s.charAt(0);if(root.next[c-'a'] != null) {sb.append(c);findPrefix(root.next[c-'a'], s.substring(1), sb);} else {sb.append(s);return;}}private void buildTrie(Trie root, String s) {if("".equals(s)) {root.end = true;return;}char c = s.charAt(0);if(root.next[c-'a'] == null)root.next[c-'a'] = new Trie();buildTrie(root.next[c-'a'], s.substring(1));}}