add: 221028

cpp/2210/221028.cpp

@@ -0,0 +1,38 @@
+#include <vector>
+#include <string>
+#include <unordered_map>
+
+/**
+ * 49. Group Anagrams
+ *
+ * Given an array of strings strs, group the anagrams together. You can return the answer in any order.
+ * An Anagram is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once.
+ */
+
+class Solution {
+private:
+	static inline long long h(const std::string& s) {
+		long long ret = 0;
+		int pos;
+		for (char c : s) {
+			pos = (c - 'a') << 1;
+			ret = (ret & ~(3LL << pos)) | (((ret >> pos & 3) + 1) & 3) << pos;
+		}
+		return ret | s.length() << 52;
+	}
+
+public:
+	static std::vector<std::vector<std::string>> groupAnagrams(const std::vector<std::string>& strs) {
+		std::unordered_map<long long, std::vector<std::string>*> m;
+		for (const std::string& s : strs) {
+			auto hash = h(s);
+			if (!m.count(hash))
+				m[hash] = new std::vector<std::string>;
+			m[hash]->push_back(s);
+		}
+		std::vector<std::vector<std::string>> ret;
+		for (const auto& [hash, ptr] : m)
+			ret.push_back(std::move(*ptr));
+		return ret;
+	}
+};

cpp/2210/CMakeLists.txt

@@ -3,4 +3,4 @@ PROJECT(2210)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2210 221027-CN.cpp)
+ADD_EXECUTABLE(2210 221028.cpp)