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637.java
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637.java
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__________________________________________________________________________________________________
sample 1 ms submission
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
class Solution {
public List<Double> averageOfLevels(TreeNode root) {
List<Double> res = new ArrayList<>();
if (root == null) return res;
Queue<TreeNode> queue = new LinkedList<>();
queue.add(root);
bfs(res, queue);
return res;
}
private void bfs(List<Double> res, Queue<TreeNode> queue) {
if (queue.isEmpty()) return;
int size = queue.size();
double sum = 0;
int curSize = size;
while (curSize -- > 0) {
TreeNode tn = queue.poll();
sum += tn.val;
if (tn.left != null) queue.add(tn.left);
if (tn.right != null) queue.add(tn.right);
}
res.add(sum / size);
bfs(res, queue);
}
}
__________________________________________________________________________________________________
sample 40104 kb submission
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
class Solution {
public List<Double> averageOfLevels(TreeNode root) {
List<Double> result = new ArrayList<>();
Queue<TreeNode> queue = new LinkedList<>();
if(root != null)
queue.add(root);
levelOrder(queue, result, queue.size());
return result;
}
public void levelOrder(Queue<TreeNode> queue, List<Double> result, int size) {
if(queue.isEmpty())
return;
int count = size; long sum = 0;
while(size > 0) {
TreeNode temp = queue.poll();
size--;
if(temp.left != null)
queue.add(temp.left);
if(temp.right != null)
queue.add(temp.right);
sum += temp.val;
}
result.add((double)(sum)/count);
levelOrder(queue, result, queue.size());
}
}
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