add: 211228

2112/211228.cpp

@@ -0,0 +1,38 @@
+#include <cstdio>
+
+/**
+ * Definition for singly-linked list.
+ */
+struct ListNode {
+	int val;
+	ListNode* next;
+	ListNode() : val(0), next(nullptr) {}
+	explicit ListNode(int x) : val(x), next(nullptr) {}
+	ListNode(int x, ListNode* next) : val(x), next(next) {}
+	~ListNode() { delete this->next; }
+};
+
+class Solution {
+public:
+	static ListNode* middleNode(const ListNode* const head) {
+		const auto* fast = head;
+		const auto* slow = fast;
+		while (fast && fast->next) {
+			fast = fast->next->next;
+			slow = slow->next;
+		}
+		return const_cast<ListNode*>(slow);
+	}
+};
+
+int main() {
+	auto* H = new ListNode(1);
+	auto* ptr = H;
+	for (int i = 2; i <= 6; ++i) {
+		ptr->next = new ListNode(i);
+		ptr = ptr->next;
+	}
+	for (const auto* M = Solution::middleNode(H); M; M = M->next)
+		std::printf("%d\n", M->val);
+	delete H;
+}

2112/CMakeLists.txt

@@ -3,4 +3,4 @@ PROJECT(2112)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2112 211227.cpp)
+ADD_EXECUTABLE(2112 211228.cpp)