Added solutio

Author: avidLearnerInProgress

cousins_binary_tree.cpp

@@ -0,0 +1,33 @@
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    int parent_x = -1, parent_y = -1, depth_x = -1, depth_y = -1, x, y;
+    
+    void findDepthAndCheckParent(TreeNode* root, int depth) {
+        if(root == NULL) return;
+        if(root->left && root->left->val == x || root->right && root->right->val == x) parent_x = root->val;
+        
+        if(root->left && root->left->val == y || root->right && root->right->val == y) parent_y = root->val;
+        if(root->val == x) depth_x = depth;
+        if(root->val == y) depth_y = depth;
+        
+        findDepthAndCheckParent(root->left, depth + 1);
+        findDepthAndCheckParent(root->right, depth + 1);
+    }
+    
+    bool isCousins(TreeNode* root, int x, int y) {
+        if(root == NULL) return false;
+        this->x = x, this->y = y;
+        findDepthAndCheckParent(root, 0);
+        return (depth_x == depth_y) && (parent_x != parent_y);
+           
+    }
+};