102. Binary Tree Level Order Traversal

102. Binary Tree Level Order Traversal.js

/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */
/**
 * @param {TreeNode} root
 * @return {number[][]}
 */
var levelOrder = function(root) {
    if(root === null) {
        return []
    }
    let queue = []
    let tempArr = [{
        level: 1,
        node: root
    }]
    let levelArr = []
    let currentLevel = 1
    let dequeued
    while(tempArr.length !==0) {
        dequeued = tempArr.shift()
        // console.log(dequeued)
        if(dequeued.level !== currentLevel) {
            queue.push(levelArr)
            levelArr = []
            currentLevel += 1
        }
        if(dequeued.level === currentLevel) {
            levelArr.push(dequeued.node.val)
        }
        if(dequeued.node.left) {
            tempArr.push({
            level: dequeued.level + 1,
            node: dequeued.node.left
             })
        }
        if(dequeued.node.right) {
            tempArr.push({
            level: dequeued.level + 1,
            node: dequeued.node.right
             })
        }        
        if(dequeued.level === currentLevel && tempArr.length === 0) {
            queue.push(levelArr)
            levelArr = []
        }
    }
    // console.log(queue)
    return queue
};