如何在Java中實現二進制表達式樹？

Question

我很努力地創建一個二進制表達式樹，並沒有找到我正在尋找什麼在線。

Answer 1

要實現它，請從包含其自己的子項的結構開始。

public class Node { 
    public Node left; 
    public Node right; 
    public String payload; 

    Node(String payload){ 
    left = null; 
    right = null; 
    this.payload = payload; 
    } 

    Node(Node left, Node right, String payload){ 
    this.left = left; 
    this.right = right; 
    this.payload = payload; 
    } 
} 

然後使用遞歸方法將結果返回給調用的方法。

int total(Node point){ 
    if (point == null) return 0; 
    switch (point.payload){ 
     case "+": return total(point.left) + total(point.right); 
     case "-": return total(point.left) - total(point.right); 
     case "/": return total(point.left)/total(point.right); 
     case "*": return total(point.left) * total(point.right); 
     default: return Integer.parseInt(point.payload); 
    } 
}