leetcode

Solution to some Leetcode problems written in C++

git clone git://git.dimitrijedobrota.com/leetcode.git

0652.cpp (909B)

0 class Solution { 1 public: 2 vector<TreeNode *> findDuplicateSubtrees(TreeNode *root) { 3 if (!root) return {}; 4 5 unordered_map<string, vector<TreeNode *>> seen; 6 unordered_map<TreeNode *, string> um; 7 vector<TreeNode *> res; 8 stack<TreeNode *> st; 9 10 st.push(root); 11 um[nullptr] = "#"; 12 while (!st.empty()) { 13 auto root = st.top(); 14 15 if (um.count(root)) { 16 um[root] = to_string(root->val) + ' ' + um[root->left] + ' ' + um[root->right]; 17 seen[um[root]].push_back(root); 18 st.pop(); 19 continue; 20 } 21 22 um[root] = ""; 23 if (root->right) st.push(root->right); 24 if (root->left) st.push(root->left); 25 } 26 27 for (const auto &[k, v] : seen) 28 if (v.size() > 1) res.push_back(v.back()); 29 30 return res; 31 } 32 };