trie 字典树构造

import org.junit.Test;
import java.util.ArrayList;

public class MyTest {
    // 单词
    class Word{
        char lastChar;  // 单词最后一个字符
        int wordCount = 0; // 词频
    }
    // 字典树
    class TreeWord{
        TreeWord parent;
        Word yourSelf = new Word();
        ArrayList children = new ArrayList<>();
    }

    // 先续遍历字典树
    public void printTreeWord(TreeWord tw){
        System.out.println(tw.yourSelf.lastChar);
        for(int i = 0; i < tw.children.size(); i ++){
            printTreeWord(tw.children.get(i));
        }
    }

    // 构造字典树
    public void buildWordTree(String str, TreeWord tw){
        TreeWord twTemp = tw;
        for(int i = 0; i < str.length(); i ++){
            char myChar = str.charAt(i);
            if(myChar == twTemp.yourSelf.lastChar && i == str.length() - 1){
                twTemp.yourSelf.wordCount ++;
            }
            boolean existInChildren = false;
            for(int j = 0; j < twTemp.children.size() && !existInChildren; j ++){
                if(twTemp.children.get(j).yourSelf.lastChar == myChar){
                    existInChildren = true;
                    twTemp = twTemp.children.get(j);
                    break;
                }
            }
            if (!existInChildren){
                TreeWord treeWordNew = new TreeWord();
                Word word = new Word();
                word.lastChar = myChar;
                treeWordNew.yourSelf = word;
                treeWordNew.parent = twTemp.parent;
                twTemp.children.add(treeWordNew);
                twTemp = treeWordNew;
            }
        }
    }

    @Test
    public void test1() throws Exception {
        String[] testWord = {"abc", "abd", "hell", "abc", "abd", "hell", "hehe"};
        TreeWord tw = new TreeWord();
        Word yourSelf = new Word();
        yourSelf.lastChar = '|';

        for(String str: testWord){
            buildWordTree(str, tw);
        }

        printTreeWord(tw);
    }
}

1. 建立字典数的时候， 并且统计词频