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authorjack <[email protected]>2024-06-14 13:13:15 -0600
committerjack <[email protected]>2024-06-14 13:13:15 -0600
commitd343a3b18dbaca9297d4f7b2280c4a16f0a5c8aa (patch)
tree96df922dae2a5073d9a50ea70c7aae6aa37e3ebe /find_duplicate_subtree.cpp
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+// 652. Find Duplicate Subtrees
+#include "leetcode.h"
+
+/*
+ * given 'root' of a binary tree, return all duplicate subtrees. for each kind
+ * of duplicate, only return the root node of any one of them. two trees are
+ * duplicate if they have the same structure with the same node values.
+ */
+
+class Solution {
+public:
+ vector<TreeNode *> findDuplicateSubtrees(TreeNode *root) {
+ unordered_map<string, vector<TreeNode *>> map;
+ vector<TreeNode *> dups;
+ serialise(root, map);
+ for (auto it = map.begin(); it != map.end(); it++)
+ if (it->second.size() > 1)
+ dups.push_back(it->second[0]);
+ return dups;
+ }
+
+private:
+ string serialise(TreeNode *node,
+ unordered_map<string, vector<TreeNode *>> &map) {
+ string s = "(" + serialise(node->left, map) + to_string(node->val) +
+ serialise(node->right, map) + ")";
+ map[s].push_back(node);
+ return s;
+ }
+};