### leetcode : Maximum Depth of Binary Tree : Iterative solution

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Here is a iterative solution on the Max Depth of a tree problem. I solved it using recursion, but then tried to solve it using an iterative process. I added comments and some extra variables for readability to make them easier to follow along

``````var maxDepth = function(root, depth=0) {
//base case: if we are given an empty or null LinkedList return 0
if(!root){return 0}
//construct the array which will hold nodes
let a = []
//currently max is 0. As we traverse tree, it will grow
let max = 0
//initialize the array by adding a node, and node depth
//in this case root and 1
a.push([root,1])
//loop through while array has elements
while(a.length > 0){
//if you are learning its easier to follow along
let node = a[0][0]
let depth = a[0][1]
//if the node has a left node or right node
//add the left and right to the array
//while incrementing the depth, because
//left or right is 1 deeper then current depth
if(node.left){a.push([node.left,depth+1])}
if(node.right){a.push([node.right,depth+1])}
//here we update the max if the depth found is greater
if(a[0][1] > max){max = a[0][1]}
//we remove the node because we no longer need it
a.shift()
}
return max
};``````