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Average of Levels in Binary Tree

Problem statement​

Given the root of a binary tree, return the average value of the nodes on each level in the form of an array. Answers within 10-5 of the actual answer will be accepted.

Example 1:

Input: root = [3,9,20,null,null,15,7]Output: [3.00000,14.50000,11.00000]Explanation: The average value of nodes on level 0 is 3, on level 1 is 14.5, and on level 2 is 11.Hence return [3, 14.5, 11].

Example 2:

Input: root = [3,9,20,15,7]Output: [3.00000,14.50000,11.00000]

Constraints:

  • The number of nodes in the tree is in the range [1, 104].
  • -231 <= Node.val <= 231 - 1

My solution​

/**
 * 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 {number[]}
 */
var averageOfLevels = function(root) {
    const queue = [root]  
  
    const results = [];
    
    while(queue.length) {
        const size = queue.length;
        let localResult = 0;
        for (let i = 0; i < size; i++) {
            const node = queue.shift();
            localResult += node.val
            
            if (node.left) {
                queue.push(node.left)
            }
            if (node.right) {
                queue.push(node.right)
            }
        }
        
        results.push(localResult/size)
    }
    
    return results;
};