add: 220311 [cpp]

cpp/2203/220311.cpp

@@ -0,0 +1,62 @@
+#include <iostream>
+
+/**
+ * Definition for singly-linked list.
+ */
+
+struct ListNode {
+	int val;
+	ListNode* next;
+
+	explicit ListNode(int x = 0, ListNode* next = nullptr) : val(x), next(next) {}
+};
+
+ListNode* construct(int x) {
+	return new ListNode(x);
+}
+
+template<typename... Ts>
+ListNode* construct(int x, Ts... xs) {
+	return new ListNode(x, construct(xs...));
+}
+
+/**
+ * 61. Rotate List
+ * Given the head of a linked list, rotate the list to the right by k places.
+ */
+
+class Solution {
+public:
+    static ListNode* rotateRight(ListNode* head, int k) {
+		if (!head || !head->next)
+			return head;
+
+        int n = 0;
+		for (auto* ptr = head; ptr; ptr = ptr->next)
+			++n;
+		int adv = (n - (k % n)) % n;
+
+		auto* ptr = head;
+		for (int i = 0; i < adv; ++i)
+			ptr = ptr->next;
+		auto* ptr2 = ptr;
+		while (ptr2->next)
+			ptr2 = ptr2->next;
+		ptr2->next = head;
+		for (auto* ptr3 = head;; ptr3 = ptr3->next) {
+			if (ptr3->next == ptr) {
+				ptr3->next = nullptr;
+				break;
+			}
+		}
+		return ptr;
+    }
+};
+
+int main() {
+	auto* head = construct(1,2);
+	head = Solution::rotateRight(head, 0);
+	for (auto* ptr = head; ptr; ptr = ptr->next)
+		std::cout << ptr->val << " ";
+	return 0;
+}

cpp/2203/CMakeLists.txt

@@ -3,4 +3,4 @@ PROJECT(2203)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2203 220311-CN.cpp)
+ADD_EXECUTABLE(2203 220311.cpp)