[JS] Binary tree average level value

binaryTreeLevelsAverage.js

// Using BFS to solve
class Node {
  constructor(data) {
    this.data = data;
    this.left = null;
    this.right = null
  }
}

function getBinaryTreeLevelsAverage(head) {
  let currentLevel = 0; 
  const queue = [[head, currentLevel]]; 
  let levelSum = 0; 
  let levelNodeCount = 0;
  const averages = []; 
  
  while(queue.length > 0) {
    const [node, level] = queue.shift(); 

    if(level === currentLevel) {
      levelNodeCount++; 
      levelSum += node.data; 
    }
    else {
      const average = levelSum / levelNodeCount;
      averages.push(average);
      
      currentLevel = level;
      levelSum = node.data;
      levelNodeCount = 1;      
    }
     
    if(node.left) queue.push([node.left, currentLevel + 1]);       
    if(node.right) queue.push([node.right, currentLevel + 1]);       
  }
  averages.push(levelSum / levelNodeCount);
  
  return averages;  
}


// ---------------------------------- Testing ---------------------------------------------------------- //
const head = new Node(4);
const node7 = new Node(7);
const node9 = new Node(9);
const node10 = new Node(10);
const node2 = new Node(2);
const node6 = new Node(6);
const node6b = new Node(6);
const node2b = new Node(2);
head.left = node7;
head.right = node9;
node7.left = node10;
node7.right = node2;
node2.right = node6b;
node6b.left = node2b;
node9.right = node6;
//       4
//      / \
//     7   9
//    / \   \
//   10  2   6
//        \
//         6
//        /
//       2    
console.log(getBinaryTreeLevelsAverage(head)); // [ 4, 8, 6, 6, 2 ]