110. Balanced Binary Tree

/**
 * Problem: LeetCode 110 - Balanced Binary Tree
 * Difficulty: Easy
 * Language: Java
 * Author: CodeByTushu
 */
/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode() {}
 *     TreeNode(int val) { this.val = val; }
 *     TreeNode(int val, TreeNode left, TreeNode right) {
 *         this.val = val;
 *         this.left = left;
 *         this.right = right;
 *     }
 * }
 */
class Solution {
    public boolean isBalanced(TreeNode root) {
        return checkHeight(root) != -1;
    }

    private int checkHeight(TreeNode node) {
        if (node == null) {
            return 0;
        }

        int leftHeight = checkHeight(node.left);
        if (leftHeight == -1) {
            return -1;
        }

        int rightHeight = checkHeight(node.right);
        if (rightHeight == -1) {
            return -1;
        }

        if (Math.abs(leftHeight - rightHeight) > 1) {
            return -1;
        }

        return 1 + Math.max(leftHeight, rightHeight);
    }
}

"""
Problem: LeetCode 110 - Balanced Binary Tree
Difficulty: Easy
Language: Python
Author: CodeByTushu
"""
from typing import Optional

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right

class Solution:
    def isBalanced(self, root: Optional[TreeNode]) -> bool:
        def check_height(node: Optional[TreeNode]) -> int:
            if not node:
                return 0

            left_height = check_height(node.left)
            if left_height == -1:
                return -1

            right_height = check_height(node.right)
            if right_height == -1:
                return -1

            if abs(left_height - right_height) > 1:
                return -1

            return 1 + max(left_height, right_height)

        return check_height(root) != -1

/**
 * Problem: LeetCode 110 - Balanced Binary Tree
 * Difficulty: Easy
 * Language: C++
 * Author: CodeByTushu
 */
#include <algorithm>
#include <cmath>

using namespace std;

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    bool isBalanced(TreeNode* root) {
        return checkHeight(root) != -1;
    }

private:
    int checkHeight(TreeNode* node) {
        if (!node) {
            return 0;
        }

        int leftHeight = checkHeight(node->left);
        if (leftHeight == -1) {
            return -1;
        }

        int rightHeight = checkHeight(node->right);
        if (rightHeight == -1) {
            return -1;
        }

        if (abs(leftHeight - rightHeight) > 1) {
            return -1;
        }

        return 1 + max(leftHeight, rightHeight);
    }
};

/**
 * Problem: LeetCode 110 - Balanced Binary Tree
 * Difficulty: Easy
 * Language: JavaScript
 * Author: CodeByTushu
 */
/**
 * Definition for a binary tree node.
 * function TreeNode(val, left, right) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.left = (left===undefined ? null : left)
 *     this.right = (right===undefined ? null : right)
 * }
 */
/**
 * @param {TreeNode} root
 * @return {boolean}
 */
var isBalanced = function(root) {
    const checkHeight = function(node) {
        if (node === null) {
            return 0;
        }

        const leftHeight = checkHeight(node.left);
        if (leftHeight === -1) {
            return -1;
        }

        const rightHeight = checkHeight(node.right);
        if (rightHeight === -1) {
            return -1;
        }

        if (Math.abs(leftHeight - rightHeight) > 1) {
            return -1;
        }

        return 1 + Math.max(leftHeight, rightHeight);
    };

    return checkHeight(root) !== -1;
};