Problem107.js

// Problem 107
//
// This problem was asked by Microsoft.
//
// Print the nodes in a binary tree level-wise. For example, the following should print 1, 2, 3, 4, 5.
//
//   1
//  / \
// 2   3
//    / \
//   4   5
//
// https://leetcode.com/problems/binary-tree-level-order-traversal/
//
// O(N) Time complexity
// O(N) Space complexity
// N is the number of nodes in the tree

/**
 * Returns the list of nodes in a binary tree level wise
 * @param {TreeNode} root
 * @return {number[]}
 */
function levelOrder(root) {
  const list = [];
  if (root === null) return list;

  const queue = [];
  queue.push(root);

  while (queue.length !== 0) {
    const node = queue.shift();
    list.push(node.val);

    if (node.left !== null) queue.push(node.left);
    if (node.right !== null) queue.push(node.right);
  }

  return list;
}

export default levelOrder;