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| class Solution {
public int countNodes(TreeNode root) {
int count = 0;
if(root == null){
return count;
}
LinkedList<TreeNode> queue = new LinkedList<>();
queue.offer(root);
while(!queue.isEmpty()){
int n = queue.size();
for(int i = 0; i < n; i++){
TreeNode node = queue.poll();
count++;
if(node.left != null){
queue.offer(node.left);
}
if(node.right != null){
queue.offer(node.right);
}
}
}
return count;
}
}
|
