愛比的新手筆記

You are given the root of a full binary tree with the following properties:

• Leaf nodes have either the value 0 or 1, where 0 represents False and 1 represents True.
• Non-leaf nodes have either the value 2 or 3, where 2 represents the boolean OR and 3 represents the boolean AND.

The evaluation of a node is as follows:

• If the node is a leaf node, the evaluation is the value of the node, i.e. True or False.
• Otherwise, evaluate the node's two children and apply the boolean operation of its value with the children's evaluations.

Return the boolean result of evaluating the root node.

A full binary tree is a binary tree where each node has either 0 or 2 children.

A leaf node is a node that has zero children.

 

Example 1:

Input: root = [2,1,3,null,null,0,1] Output: true Explanation: The above diagram illustrates the evaluation process. The AND node evaluates to False AND True = False. The OR node evaluates to True OR False = True. The root node evaluates to True, so we return true.

Example 2:

Input: root = [0] Output: false Explanation: The root node is a leaf node and it evaluates to false, so we return false.

 

Constraints:

• The number of nodes in the tree is in the range [1, 1000].
• 0 <= Node.val <= 3
• Every node has either 0 or 2 children.
• Leaf nodes have a value of 0 or 1.
• Non-leaf nodes have a value of 2 or 3.

將每個node值依下述轉換:
0:false
1:true
2:or
3:and
左右腳值以上一層node指示計算, 回傳最後結果

public class Solution {
        public bool EvaluateTree(TreeNode root)
        {
            switch (root.val)
            {
                case 1:
                    return true;
                case 2:
                    return EvaluateTree(root.left) || EvaluateTree(root.right);
                case 3:
                    return EvaluateTree(root.left) && EvaluateTree(root.right);
            }
            return false;
        }
}

Taiwan is a country. 臺灣是我的國家