by Pawan Kumar @jsartisan
Given the root of a binary tree, return its depth.
The depth of a binary tree is defined as the number of nodes along the longest path from the root node down to the farthest leaf node.
Constraints:
- 0 ≤ Number of nodes in the tree ≤ 100
- -100 ≤ Node value ≤ 100
Examples:
// Example 1:
// 1
// / \
// 2 3
// /
// 4
const root1 = createTree([1, 2, 3, null, null, 4]);
console.log(maxDepth(root1));
// Output: 3
// Example 2:
const root2 = createTree([]);
console.log(maxDepth(root2));
// Output: 0
// Example 3:
// 1
// / \
// 2 3
// / \ / \
// 4 5 6 7
const root3 = createTree([1, 2, 3, 4, 5, 6, 7]);
console.log(maxDepth(root3));
// Output: 3
