652. Find Duplicate Subtrees

Author: amitbansal7

find-duplicate-subtrees.cpp

@@ -0,0 +1,27 @@
+//Runtime: 32 ms
+class Solution {
+public:
+
+    string serialize(TreeNode* root, unordered_map<string, vector<TreeNode*> > &Mp)
+    {
+        if(!root)
+            return "";
+
+        string s = "(" + serialize(root->left, Mp) + to_string(root->val) + serialize(root->right, Mp) + ")";
+        Mp[s].push_back(root);
+        return s;
+    }
+
+    vector<TreeNode*> findDuplicateSubtrees(TreeNode* root) {
+        vector<TreeNode* > res;
+        unordered_map<string, vector<TreeNode* > > Mp;
+        serialize(root, Mp);
+
+        for(auto it:Mp)
+        {
+            if(it.second.size() > 1)
+                res.push_back(it.second[0]);
+        }
+        return res;
+    }
+};