Finding the maximum depth of a binary tree in JavaScript.

binaryTree-max-depth.js

/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */
/**
 * @param {TreeNode} root
 * @return {number}
 */
var maxDepth = function(root) {
    var fringe = [{ node: root, depth: 1 }];
    var current = fringe.pop();
    var max = 0;

    while (current && current.node) {
        var node = current.node;
        
        // Find all children of this node.
        if (node.left) {
            fringe.push({ node: node.left, depth: current.depth + 1 });
        }
        if (node.right) {
            fringe.push({ node: node.right, depth: current.depth + 1 });
        }
    
        if (current.depth > max) {
            max = current.depth;
        }
        
        current = fringe.pop();
    }

    return max;
};

zexample.txt

Given a binary tree, find its maximum depth.

The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.