Given a non-empty binary tree, return the average value of the nodes on each level in the form of an array.
Example
Input:
Output: [3, 14.5, 11]
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].
Note
- The range of node’s value is in the range of 32-bit signed integer.
Code
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public class { int val; TreeNode left; TreeNode right; TreeNode(int x) { val = x; } }
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public List<Double> averageOfLevels(TreeNode root) { List<Double> result = new ArrayList<>();
if (root == null) return result;
Queue<TreeNode> queue = new LinkedList<>(); queue.offer(root);
while (!queue.isEmpty()) { int size = queue.size(); long sum = 0;
for (int i = 0; i < size; i++) { TreeNode node = queue.poll(); sum += node.val;
if (node.left != null) queue.offer(node.left); if (node.right != null) queue.offer(node.right); }
result.add(sum * 1.0 / size); }
return result; }
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