add: 220404 [cpp]

cpp/2204/220404.cpp

@@ -0,0 +1,29 @@
+#include <algorithm>
+
+/**
+ * Definition for singly-linked list.
+ */
+struct ListNode {
+	int val;
+	ListNode* next;
+	explicit ListNode(int x, ListNode* n = nullptr) : val(x), next(n) {}
+	~ListNode() { delete this->next; this->next = nullptr; }
+};
+
+class Solution {
+public:
+	static ListNode* swapNodes(ListNode* head, int k) {
+		if (!head || !head->next) return head;
+		auto* fast = head;
+		for (int i = 1; i < k; ++i)
+			fast = fast->next;
+		auto* slow = head;
+		auto* S1 = fast;
+		while (fast->next) {
+			fast = fast->next;
+			slow = slow->next;
+		}
+		std::swap(slow->val, S1->val);
+		return head;
+	}
+};

cpp/2204/CMakeLists.txt

@@ -3,4 +3,4 @@ PROJECT(2204)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2204 220403-CN.cpp)
+ADD_EXECUTABLE(2204 220404.cpp)