993. Cousins in Binary Tree

Author: amitbansal7

cousins-in-binary-tree.cpp

@@ -0,0 +1,34 @@
+// Runtime: 8 ms
+// Memory Usage: 11.9 MB
+class Solution {
+public:
+
+  TreeNode* findParent(TreeNode* root, int d, int val, int &depth) {
+    if (!root) return NULL;
+
+    if (root->left && root->left->val == val) {
+      depth = d;
+      return root;
+    }
+
+    if (root->right && root->right->val == val) {
+      depth = d;
+      return root;
+    }
+
+    TreeNode* l = findParent(root->left, d + 1, val, depth);
+    if (l != NULL) {
+      return l;
+    }
+
+    return findParent(root->right, d + 1, val, depth);
+  }
+
+  bool isCousins(TreeNode* root, int x, int y) {
+    int xd = -1;
+    int yd = -1;
+    TreeNode* lp = findParent(root, 0, x, xd);
+    TreeNode* rp = findParent(root, 0, y, yd);
+    return lp != rp && xd == yd;
+  }
+};