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### by Sumit Chourasia | Oct 09, 2020 | Category :coding | Tags : algorithmbinary-treedata-structureeasyleetcodetree #### Cousins in Binary Tree - Tree - Easy - LeetCode

In a binary tree, the root node is at depth 0, and children of each depth k node are at depth k+1.

Two nodes of a binary tree are cousins if they have the same depth, but have different parents.

We are given the root of a binary tree with unique values, and the values x and y of two different nodes in the tree.

Return true if and only if the nodes corresponding to the values x and y are cousins.

Example 1:

Input: root = [1,2,3,4], x = 4, y = 3
Output: false
Example 2:

Input: root = [1,2,3,null,4,null,5], x = 5, y = 4
Output: true
Example 3:

Input: root = [1,2,3,null,4], x = 2, y = 3
Output: false

Constraints:

The number of nodes in the tree will be between 2 and 100.
Each node has a unique integer value from 1 to 100.

``````/**
* 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 bool IsCousins(TreeNode root, int x, int y) {
if(root == null){
return false;
}

var queue = new Queue<TreeNode>();
queue.Enqueue(root);
while(queue.Count()>0){
int count = queue.Count();
bool foundx = false;
bool foundy = false;
while(count-->0){
var node = queue.Dequeue();
if(node.val==x){
foundx=true;
}
if(node.val==y){
foundy=true;
}

if(node.left != null && node.right != null){
if(node.left.val ==x && node.right.val == y){
return false;
}
if(node.right.val==x && node.left.val==y){
return false;
}
}

if(node.left != null){
queue.Enqueue(node.left);
}
if(node.right != null){
queue.Enqueue(node.right);
}

}
if(foundx && foundy)
{
return true;
}
}

return false;
}
}``````

Time Complexity: O(n)

Space Complexity: O(height)