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Maximum Level Sum of a Binary Tree

Problem statement​

Given the root of a binary tree, the level of its root is 1, the level of its children is 2, and so on.

Return the smallest level x such that the sum of all the values of nodes at level x is maximal.

Example 1:

Input: root = [1,7,0,7,-8,null,null]Output: 2Explanation: Level 1 sum = 1.Level 2 sum = 7 + 0 = 7.Level 3 sum = 7 + -8 = -1.So we return the level with the maximum sum which is level 2.

Example 2:

Input: root = [989,null,10250,98693,-89388,null,null,null,-32127]Output: 2

Constraints:

  • The number of nodes in the tree is in the range [1, 104].
  • -105 <= Node.val <= 105

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 maxLevelSum = function(root) {
    const queue = [root];
    let level = 1;
    let maxValue = Number.MIN_SAFE_INTEGER;
    let maxValueLevel = -1;
    
    while(queue.length) {
        const size = queue.length;
        
        let levelSum = 0;
        for (let i = 0; i < size; i++) {
            const node = queue.shift();
            
            levelSum += node.val;
            
            if (node.left) {
                queue.push(node.left)
            }
            if (node.right) {
                queue.push(node.right)
            }
        }
        
        if (levelSum > maxValue) {
            maxValue = levelSum;
            maxValueLevel = level;
        }
        
        level++
    }
    
    return maxValueLevel
};