Create cousinsInBinaryTree.cpp

DFS/cousinsInBinaryTree.cpp

@@ -0,0 +1,44 @@
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
+ *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
+ *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
+ * };
+ */
+class Solution
+{
+    vector<pair<TreeNode *, int>> res;
+
+public:
+    void dfs(TreeNode *node, TreeNode *root, int depth, int x, int y)
+    {
+        if (!node)
+            return;
+
+        if (node->val == x)
+        {
+            res.emplace_back(root, depth);
+        }
+
+        if (node->val == y)
+        {
+            res.emplace_back(root, depth);
+        }
+
+        dfs(node->left, node, depth + 1, x, y);
+        dfs(node->right, node, depth + 1, x, y);
+    }
+    bool isCousins(TreeNode *root, int x, int y)
+    {
+        dfs(root, nullptr, 0, x, y);
+
+        auto node_x = res[0];
+        auto node_y = res[1];
+
+        return node_x.first != node_y.first and node_x.second == node_y.second;
+    }
+};