爲二叉搜索樹編寫插入方法

Question

我試圖實現方法在Java中創建二進制搜索樹，最終將能夠創建一個字引用報告。

我的問題是我無法讓我的insertItem方法正確編譯。

行else if(word.compareTo(r.item)){給出的編譯器錯誤指向r.item，並表示它不能轉換爲字符串。我該怎麼做才能解決這個問題？

public void insert(String word) { 
    root = insertItem(root, word); 
} 

protected TreeNode insertItem(TreeNode r, String word) { 
    //base case 
    if (r==null) { 
     new TreeNode(new WordRefs(word)); 
    } 
    else if (word.compareTo(r.item)) { 
     r.left = insertItem(r.left, word); 
    } else { 
     r.right = insertItem(r.right, word); 
    } 
    return r; 
} 

public class WordRefs { 

    private String word; 
    private LinkedList<Integer> lineNumbers; 

    public WordRefs(String word) { 
     this.word = word; 
     lineNumbers = new LinkedList<>(); 
    } 

    public void addLine(int lineNumber) { 
     lineNumbers.add(lineNumber); 
    } 

    public String getWord() { 
     return word; 
    } 

    public LinkedList<Integer> getLineNumbers() { 
     return lineNumbers; 
    } 

    public String toString() { 
     String result = word + ":"; 
     for (Integer ii : lineNumbers) { 
      result += " " + ii; 
     } 
     return result; 
    } 
} 

class TreeNode { 
    WordRefs item; 
    TreeNode left; 
    TreeNode right; 

    public TreeNode(WordRefs item) { 
     this.item = item; 
     this.left = this.right = null; 
    } 

    public TreeNode(WordRefs item, TreeNode left, TreeNode right) { 
     this.item = item; 
     this.left = left; 
     this.right = right; 
    } 
} 

Answer 1

您插入功能應該是這樣的，你必須使用從WordReft屏幕取詞（）函數，它應該是< = 0轉到左側> 0轉到右

protected TreeNode insertItem(TreeNode r, String word) { 
//base case 
if(r==null){ 
r = new TreeNode(new WordRefs(word)); 
    } 
else if(word.compareTo(r.item.getWord()) <= 0){ 
    r.left = insertItem(r.left, word); 
}else{ 
    r.right = insertItem(r.right, word); 
} 
return r; 
}