Leetcode 222. Count Complete Tree Nodes

222. Count Complete Tree Nodes

アプローチ

DFS

class Solution {
    public int countNodes(TreeNode root) {
        int size = 1;
        if(root == null){
            return 0;
        }
  
        if(root.left != null){
            size += countNodes(root.left) ;
        }
         if(root.right != null){
            size += countNodes(root.right) ;
        }
        return size ;
    }
}