add: 230413-CN

cpp/2304/230413-CN.cpp

@@ -0,0 +1,27 @@
+#include <iterator>
+#include <unordered_map>
+#include <vector>
+#include <algorithm>
+
+/**
+ * 2404. Most Frequent Even Element
+ *
+ * Given an integer array nums, return the most frequent even element.
+ * If there is a tie, return the smallest one. If there is no such element, return -1.
+ */
+
+class Solution {
+	using LL = long long;
+public:
+	static int mostFrequentEven(const std::vector<int>&);
+};
+
+int Solution::mostFrequentEven(const std::vector<int>& n) {
+	std::unordered_map<int, int> m;
+	std::for_each(n.begin(), n.end(), [&](int x) { if (!(x & 1)) ++m[x]; });
+	return m.empty() ? -1 : std::max_element(m.begin(), m.end(), [](auto&& x, auto&& y) {
+		auto&& [xk, xs] = x;
+		auto&& [yk, ys] = y;
+		return (LL(xs) << 32) - xk < (LL(ys) << 32) - yk;
+	})->first;
+}

cpp/2304/CMakeLists.txt

@@ -4,4 +4,4 @@ PROJECT(2304)
 SET(CMAKE_CXX_STANDARD 23)
 SET(CMAKE_EXPORT_COMPILE_COMMANDS true)
 
-ADD_EXECUTABLE(2304 230412-CN.cpp)
+ADD_EXECUTABLE(2304 230413-CN.cpp)