25. Reverse Nodes in k-Group
阿新 • • 發佈:2021-11-04
LeetCode、連結串列
SLinkedList<int> slist = new SLinkedList<int>(); slist.AppendRange(new[] { 1, 2, 3, 4, 5 }); Console.WriteLine("Input: " + slist.Print()); Console.WriteLine("k = 2"); var rslt = slist.ReverseKGroup(2); Console.WriteLine("Output:" + rslt.Print()); Console.WriteLine("k = 3"); rslt = slist.ReverseKGroup(3); Console.WriteLine("Output:" + rslt.Print());
/// <summary> /// k 個相鄰的元素,翻轉連結串列,多餘的繼續保持 /// </summary> /// <typeparam name="T"></typeparam> /// <param name="source"></param> /// <param name="k"></param> /// <returns></returns> public static SLinkedList<T> ReverseKGroup<T>(this SLinkedList<T> source, int k) where T : IComparable<T> { var tmp = new SLinkedList<T>(source); var node = ReverseKGroupImp(tmp.Head, k); return new SLinkedList<T>(node); } private static SLinkedListNode<T> ReverseKGroupImp<T>(SLinkedListNode<T> head, int k) where T : IComparable<T> { var node = head; for (int i = 0; i < k; i++) { if (node == null) { return head; } node = node.Next; } var newHead = Reverse(head, node); head.Next = ReverseKGroupImp(node, k); return newHead; } private static SLinkedListNode<T> Reverse<T>(SLinkedListNode<T> first, SLinkedListNode<T> last) where T : IComparable<T> { var prev = last; while (first != last) { var tmp = first.Next; first.Next = prev; prev = first; first = tmp; } return prev; }