Find All The Lonely Nodes

LeetCode Link

Problem Description

Visit LeetCode for the full problem description.

---

Solutions

Solution 1: C# (Best: 228 ms)

Metric	Value
Runtime	228 ms
Memory	34.3 MB
Date	2021-10-02

Solution

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     public int val;
 *     public TreeNode left;
 *     public TreeNode right;
 *     public TreeNode(int val=0, TreeNode left=null, TreeNode right=null) {
 *         this.val = val;
 *         this.left = left;
 *         this.right = right;
 *     }
 * }
 */
public class Solution {
    public IList<int> GetLonelyNodes(TreeNode root) {
      List<int> result = new List<int>();
    helper(root, result);
    return result;
}

private void helper(TreeNode root, List<int> result)
{
    if (root == null)
    {
        return;
    }
    
    if(root.left==null && root.right!= null)
    {
        result.Add(root.right.val);
    }
    if (root.left != null && root.right == null)
    {
        result.Add(root.left.val);
    }
    
    helper(root.left, result);
    helper(root.right, result);

}
}

---

Complexity Analysis

Approach	Time	Space
Solution	To be analyzed	To be analyzed