2331. Evaluate Boolean Binary Tree

Easy

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.

解題

/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */
func evaluateTree(root *TreeNode) bool {
    if root.Val == 0 {
        return false
    } else if root.Val == 1 {
        return true
    } else if root.Val == 2 {
        return evaluateTree(root.Left) || evaluateTree(root.Right)
    }

    return evaluateTree(root.Left) && evaluateTree(root.Right)
}