Title Top google leetcode questions.pdf ✅

409. Longest Palindrome 415. Add Strings 429. N-ary Tree Level Order Traversal 438. Find All Anagrams in a String 447. Number of Boomerangs 451. Sort Characters By Frequency 468. Validate IP Address 470. Implement Rand10() Using Rand7() 475. Heaters 482. License Key Formatting 498. Diagonal Traverse 510. Inorder Successor in BST II 518. Coin Change 2 525. Contiguous Array 528. Random Pick with Weight 535. Encode and Decode TinyURL 540. Single Element in a Sorted Array 542. 01 Matrix 551. Student Attendance Record I 567. Permutation in String
249. Group Shifted Strings Description Solution 05/25/2020: Given a string, we can "shift" each of its letter to its successive letter, for example: "abc" -> "bcd". We can keep "shifting" which forms the sequence: "abc" -> "bcd" -> ... -> "xyz" Given a list of strings which contains only lowercase alphabets, group all strings that belong to the same shifting sequence. Example: Input: ["abc", "bcd", "acef", "xyz", "az", "ba", "a", "z"], Output: [ ["abc","bcd","xyz"], ["az","ba"], ["acef"], ["a","z"] ]
250. Count Univalue Subtrees Description class Solution { public: vector> groupStrings(vector& strings) { unordered_map> shiftedStrings; for (auto& s : strings) shiftedStrings[hash(s)].push_back(s); vector> ret; for (auto& m : shiftedStrings) ret.push_back(m.second); return ret; } int hash(const string& s) { long long h = 1; if (s.empty()) return h; int offset = s[0] - 'a'; string ts; const int MOD = 1e9 + 7; for (auto& c : s) ts += (c - 'a' - offset + 26) % 26 + 'a'; for (auto& c : ts) h = (h * 31 + c - 'a') % MOD; return h; } };