明智地旋转链表

给定一个长度为 n 和块长度k的链表，将每个块向右/向左旋转一个数字d 。如果d是正向旋转，则向右旋转，否则向左旋转。

例子：

Input: 1->2->3->4->5->6->7->8->9->NULL, 
        k = 3 
        d = 1
Output: 3->1->2->6->4->5->9->7->8->NULL
Explanation: Here blocks of size 3 are
rotated towards right(as d is positive) 
by 1.
 
Input: 1->2->3->4->5->6->7->8->9->10->
               11->12->13->14->15->NULL, 
        k = 4 
        d = -1
Output: 2->3->4->1->6->7->8->5->10->11
             ->12->9->14->15->13->NULL
Explanation: Here, at the end of linked 
list, remaining nodes are less than k, i.e.
only three nodes are left while k is 4. 
Rotate those 3 nodes also by d.

先决条件：旋转链表
思路是如果 d 的绝对值大于 k 的值，则将链表旋转 d % k 次。如果 d 为 0，则根本不需要旋转链表。

C++

// C++ program to rotate a linked list block wise
#include
using namespace std;
 
/* Link list node */
class Node
{
    public:
    int data;
    Node* next;
};
 
// Recursive function to rotate one block
Node* rotateHelper(Node* blockHead,
                        Node* blockTail,
                        int d, Node** tail,
                        int k)
{
    if (d == 0)
        return blockHead;
 
    // Rotate Clockwise
    if (d > 0)
    {
        Node* temp = blockHead;
        for (int i = 1; temp->next->next &&
                        i < k - 1; i++)
            temp = temp->next;
        blockTail->next = blockHead;
        *tail = temp;
        return rotateHelper(blockTail, temp,
                            d - 1, tail, k);
    }
 
    // Rotate anti-Clockwise
    if (d < 0)
    {
        blockTail->next = blockHead;
        *tail = blockHead;
        return rotateHelper(blockHead->next,
                blockHead, d + 1, tail, k);
    }
}
 
// Function to rotate the linked list block wise
Node* rotateByBlocks(Node* head,
                                int k, int d)
{
    // If length is 0 or 1 return head
    if (!head || !head->next)
        return head;
 
    // if degree of rotation is 0, return head
    if (d == 0)
        return head;
 
    Node* temp = head, *tail = NULL;
 
    // Traverse upto last element of this block
    int i;
    for (i = 1; temp->next && i < k; i++)
        temp = temp->next;
 
    // storing the first node of next block
    Node* nextBlock = temp->next;
 
    // If nodes of this block are less than k.
    // Rotate this block also
    if (i < k)
        head = rotateHelper(head, temp, d % k,
                                    &tail, i);
    else
        head = rotateHelper(head, temp, d % k,
                                    &tail, k);
 
    // Append the new head of next block to
    // the tail of this block
    tail->next = rotateByBlocks(nextBlock, k,
                                    d % k);
 
    // return head of updated Linked List
    return head;
}
 
/* UTILITY FUNCTIONS */
/* Function to push a node */
void push(Node** head_ref, int new_data)
{
    Node* new_node = new Node;
    new_node->data = new_data;
    new_node->next = (*head_ref);
    (*head_ref) = new_node;
}
 
/* Function to print linked list */
void printList(Node* node)
{
    while (node != NULL)
    {
        cout << node->data << " ";
        node = node->next;
    }
}
 
/* Driver code*/
int main()
{
    /* Start with the empty list */
    Node* head = NULL;
 
    // create a list 1->2->3->4->5->
    // 6->7->8->9->NULL
    for (int i = 9; i > 0; i -= 1)
        push(&head, i);
 
    cout<<"Given linked list \n";
    printList(head);
 
    // k is block size and d is number of
    // rotations in every block.
    int k = 3, d = 2;
    head = rotateByBlocks(head, k, d);
 
    cout << "\nRotated by blocks Linked list \n";
    printList(head);
 
    return (0);
}
 
// This is code is contributed by rathbhupendra

C

// C program to rotate a linked list block wise
#include 
#include 
 
/* Link list node */
struct Node {
    int data;
    struct Node* next;
};
 
// Recursive function to rotate one block
struct Node* rotateHelper(struct Node* blockHead,
                          struct Node* blockTail,
                          int d, struct Node** tail,
                          int k)
{
    if (d == 0)
        return blockHead;
 
    // Rotate Clockwise
    if (d > 0) {
        struct Node* temp = blockHead;
        for (int i = 1; temp->next->next &&
                        i < k - 1; i++)
            temp = temp->next;
        blockTail->next = blockHead;
        *tail = temp;
        return rotateHelper(blockTail, temp,
                            d - 1, tail, k);
    }
 
    // Rotate anti-Clockwise
    if (d < 0) {
        blockTail->next = blockHead;
        *tail = blockHead;
        return rotateHelper(blockHead->next,
                blockHead, d + 1, tail, k);
    }
}
 
// Function to rotate the linked list block wise
struct Node* rotateByBlocks(struct Node* head,
                                 int k, int d)
{
    // If length is 0 or 1 return head
    if (!head || !head->next)
        return head;
 
    // if degree of rotation is 0, return head
    if (d == 0)
        return head;
 
    struct Node* temp = head, *tail = NULL;
 
    // Traverse upto last element of this block
    int i;
    for (i = 1; temp->next && i < k; i++)
        temp = temp->next;
 
    // storing the first node of next block
    struct Node* nextBlock = temp->next;
 
    // If nodes of this block are less than k.
    // Rotate this block also
    if (i < k)
        head = rotateHelper(head, temp, d % k,
                                    &tail, i);
    else
        head = rotateHelper(head, temp, d % k,
                                    &tail, k);
 
    // Append the new head of next block to
    // the tail of this block
    tail->next = rotateByBlocks(nextBlock, k,
                                      d % k);
 
    // return head of updated Linked List
    return head;
}
 
/* UTILITY FUNCTIONS */
/* Function to push a node */
void push(struct Node** head_ref, int new_data)
{
    struct Node* new_node = new Node;
    new_node->data = new_data;
    new_node->next = (*head_ref);
    (*head_ref) = new_node;
}
 
/* Function to print linked list */
void printList(struct Node* node)
{
    while (node != NULL) {
        printf("%d ", node->data);
        node = node->next;
    }
}
 
/* Driver program to test above function*/
int main()
{
    /* Start with the empty list */
    struct Node* head = NULL;
 
    // create a list 1->2->3->4->5->
    // 6->7->8->9->NULL
    for (int i = 9; i > 0; i -= 1)
        push(&head, i);
 
    printf("Given linked list \n");
    printList(head);
 
    // k is block size and d is number of
    // rotations in every block.
    int k = 3, d = 2;
    head = rotateByBlocks(head, k, d);
 
    printf("\nRotated by blocks Linked list \n");
    printList(head);
 
    return (0);
}

Java

// Java program to rotate a linked list block wise
import java.util.*;
class GFG
{
 
/* Link list node */
static class Node
{
    int data;
    Node next;
};
static Node tail;
   
// Recursive function to rotate one block
static Node rotateHelper(Node blockHead,
                        Node blockTail,
                        int d,
                        int k)
{
    if (d == 0)
        return blockHead;
 
    // Rotate Clockwise
    if (d > 0)
    {
        Node temp = blockHead;
        for (int i = 1; temp.next.next!=null &&
                        i < k - 1; i++)
            temp = temp.next;
        blockTail.next = blockHead;
        tail = temp;
        return rotateHelper(blockTail, temp,
                            d - 1,  k);
    }
 
    // Rotate anti-Clockwise
    if (d < 0)
    {
        blockTail.next = blockHead;
        tail = blockHead;
        return rotateHelper(blockHead.next,
                blockHead, d + 1,  k);
    }
    return blockHead;
}
 
// Function to rotate the linked list block wise
static Node rotateByBlocks(Node head,
                                int k, int d)
{
    // If length is 0 or 1 return head
    if (head == null || head.next == null)
        return head;
 
    // if degree of rotation is 0, return head
    if (d == 0)
        return head;
 
    Node temp = head;
    tail = null;
 
    // Traverse upto last element of this block
    int i;
    for (i = 1; temp.next != null && i < k; i++)
        temp = temp.next;
 
    // storing the first node of next block
    Node nextBlock = temp.next;
 
    // If nodes of this block are less than k.
    // Rotate this block also
    if (i < k)
        head = rotateHelper(head, temp, d % k,
                                   i);
    else
        head = rotateHelper(head, temp, d % k,
                                    k);
 
    // Append the new head of next block to
    // the tail of this block
    tail.next = rotateByBlocks(nextBlock, k,
                                    d % k);
 
    // return head of updated Linked List
    return head;
}
 
/* UTILITY FUNCTIONS */
/* Function to push a node */
static Node push(Node head_ref, int new_data)
{
    Node new_node = new Node();
    new_node.data = new_data;
    new_node.next = head_ref;
    head_ref = new_node;
    return head_ref;
     
}
 
/* Function to print linked list */
static void printList(Node node)
{
    while (node != null)
    {
        System.out.print(node.data + " ");
        node = node.next;
    }
}
 
/* Driver code*/
public static void main(String[] args)
{
   
    /* Start with the empty list */
    Node head = null;
 
    // create a list 1.2.3.4.5.
    // 6.7.8.9.null
    for (int i = 9; i > 0; i -= 1)
        head = push(head, i);
    System.out.print("Given linked list \n");
    printList(head);
 
    // k is block size and d is number of
    // rotations in every block.
    int k = 3, d = 2;
    head = rotateByBlocks(head, k, d);
    System.out.print("\nRotated by blocks Linked list \n");
    printList(head);
}
}
 
// This code contributed by aashish1995

Python3

# Python3 program to rotate a linked
# list block wise
 
# Link list node
class Node:   
    def __init__(self, data):     
        self.data = data
        self.next = None
 
# Recursive function to rotate one block
def rotateHelper(blockHead, blockTail,
                 d, tail, k):   
    if (d == 0):
        return blockHead, tail
  
    # Rotate Clockwise
    if (d > 0):
        temp = blockHead
        i = 1       
        while temp.next.next != None and i < k - 1:
            temp = temp.next
            i += 1           
        blockTail.next = blockHead
        tail = temp
        return rotateHelper(blockTail, temp,
                            d - 1, tail, k)
 
    # Rotate anti-Clockwise
    if (d < 0):
        blockTail.next = blockHead
        tail = blockHead
        return rotateHelper(blockHead.next,
                            blockHead, d + 1,
                            tail, k)
     
# Function to rotate the linked list block wise
def rotateByBlocks(head, k, d):
 
    # If length is 0 or 1 return head
    if (head == None or head.next == None):
        return head
  
    # If degree of rotation is 0, return head
    if (d == 0):
        return head
    temp = head
    tail = None
  
    # Traverse upto last element of this block
    i = 1   
    while temp.next != None and i < k:
        temp = temp.next
        i += 1
  
    # Storing the first node of next block
    nextBlock = temp.next
  
    # If nodes of this block are less than k.
    # Rotate this block also
    if (i < k):
        head, tail = rotateHelper(head, temp, d % k,
                                  tail, i)
    else:
        head, tail = rotateHelper(head, temp, d % k,
                                  tail, k)
  
    # Append the new head of next block to
    # the tail of this block
    tail.next = rotateByBlocks(nextBlock, k,
                               d % k);
  
    # Return head of updated Linked List
    return head;
 
# UTILITY FUNCTIONS
# Function to push a node
def push(head_ref, new_data):
 
    new_node = Node(new_data)
    new_node.data = new_data
    new_node.next = (head_ref)
    (head_ref) = new_node
    return head_ref
 
# Function to print linked list
def printList(node):
    while (node != None):
        print(node.data, end = ' ')
        node = node.next
     
# Driver code
if __name__=='__main__':
     
    # Start with the empty list
    head = None
  
    # Create a list 1.2.3.4.5.
    # 6.7.8.9.None
    for  i in range(9, 0, -1):
        head = push(head, i)
    print("Given linked list ")
    printList(head)
  
    # k is block size and d is number of
    # rotations in every block.
    k = 3
    d = 2
    head = rotateByBlocks(head, k, d)
  
    print("\nRotated by blocks Linked list ")
    printList(head)
  
# This code is contributed by rutvik_56

C#

// C# program to rotate a linked list block wise
using System;
public class GFG
{
 
  /* Link list node */
  public
    class Node
    {
      public
        int data;
      public
        Node next;
    };
  static Node tail;
 
  // Recursive function to rotate one block
  static Node rotateHelper(Node blockHead,
                           Node blockTail,
                           int d,
                           int k)
  {
    if (d == 0)
      return blockHead;
 
    // Rotate Clockwise
    if (d > 0)
    {
      Node temp = blockHead;
      for (int i = 1; temp.next.next != null &&
           i < k - 1; i++)
        temp = temp.next;
      blockTail.next = blockHead;
      tail = temp;
      return rotateHelper(blockTail, temp,
                          d - 1, k);
    }
 
    // Rotate anti-Clockwise
    if (d < 0)
    {
      blockTail.next = blockHead;
      tail = blockHead;
      return rotateHelper(blockHead.next,
                          blockHead, d + 1,  k);
    }
    return blockHead;
  }
 
  // Function to rotate the linked list block wise
  static Node rotateByBlocks(Node head,
                             int k, int d)
  {
    // If length is 0 or 1 return head
    if (head == null || head.next == null)
      return head;
 
    // if degree of rotation is 0, return head
    if (d == 0)
      return head;
    Node temp = head;
    tail = null;
 
    // Traverse upto last element of this block
    int i;
    for (i = 1; temp.next != null && i < k; i++)
      temp = temp.next;
 
    // storing the first node of next block
    Node nextBlock = temp.next;
 
    // If nodes of this block are less than k.
    // Rotate this block also
    if (i < k)
      head = rotateHelper(head, temp, d % k,
                          i);
    else
      head = rotateHelper(head, temp, d % k,
                          k);
 
    // Append the new head of next block to
    // the tail of this block
    tail.next = rotateByBlocks(nextBlock, k,
                               d % k);
 
    // return head of updated Linked List
    return head;
  }
 
  /* UTILITY FUNCTIONS */
  /* Function to push a node */
  static Node push(Node head_ref, int new_data)
  {
    Node new_node = new Node();
    new_node.data = new_data;
    new_node.next = head_ref;
    head_ref = new_node;
    return head_ref;
 
  }
 
  /* Function to print linked list */
  static void printList(Node node)
  {
    while (node != null)
    {
      Console.Write(node.data + " ");
      node = node.next;
    }
  }
 
  /* Driver code*/
  public static void Main(String[] args)
  {
 
    /* Start with the empty list */
    Node head = null;
 
    // create a list 1.2.3.4.5.
    // 6.7.8.9.null
    for (int i = 9; i > 0; i -= 1)
      head = push(head, i);
    Console.Write("Given linked list \n");
    printList(head);
 
    // k is block size and d is number of
    // rotations in every block.
    int k = 3, d = 2;
    head = rotateByBlocks(head, k, d);
    Console.Write("\nRotated by blocks Linked list \n");
    printList(head);
  }
}
 
// This code is contributed by aashish1995

Javascript

 
// JavaScript program to rotate a
// linked list block wise
 
    /* Link list node */
class Node {
    constructor() {
        this.data = 0;
        this.next = null;
    }
}
 
    var tail;
 
    // Recursive function to rotate one block
    function rotateHelper(blockHead,  blockTail , d , k)
    {
        if (d == 0)
            return blockHead;
 
        // Rotate Clockwise
        if (d > 0) {
            var temp = blockHead;
            for (i = 1; temp.next.next != null &&
            i < k - 1; i++)
                temp = temp.next;
            blockTail.next = blockHead;
            tail = temp;
            return rotateHelper(blockTail,
            temp, d - 1, k);
        }
 
        // Rotate anti-Clockwise
        if (d < 0) {
            blockTail.next = blockHead;
            tail = blockHead;
            return rotateHelper(blockHead.next,
            blockHead, d + 1, k);
        }
        return blockHead;
    }
 
    // Function to rotate the linked list block wise
    function rotateByBlocks(head , k , d) {
        // If length is 0 or 1 return head
        if (head == null || head.next == null)
            return head;
 
        // if degree of rotation is 0, return head
        if (d == 0)
            return head;
 
var temp = head;
        tail = null;
 
        // Traverse upto last element of this block
        var i;
        for (i = 1; temp.next != null && i < k; i++)
            temp = temp.next;
 
        // storing the first node of next block
var nextBlock = temp.next;
 
        // If nodes of this block are less than k.
        // Rotate this block also
        if (i < k)
            head = rotateHelper(head, temp, d % k, i);
        else
            head = rotateHelper(head, temp, d % k, k);
 
        // Append the new head of next block to
        // the tail of this block
        tail.next = rotateByBlocks(nextBlock, k, d % k);
 
        // return head of updated Linked List
        return head;
    }
 
    /* UTILITY FUNCTIONS */
    /* Function to push a node */
    function push(head_ref , new_data) {
var new_node = new Node();
        new_node.data = new_data;
        new_node.next = head_ref;
        head_ref = new_node;
        return head_ref;
 
    }
 
    /* Function to print linked list */
    function printList(node) {
        while (node != null) {
            document.write(node.data + " ");
            node = node.next;
        }
    }
 
    /* Driver code */
     
 
        /* Start with the empty list */
var head = null;
 
        // create a list 1.2.3.4.5.
        // 6.7.8.9.null
        for (i = 9; i > 0; i -= 1)
            head = push(head, i);
        document.write("Given linked list <br/>");
        printList(head);
 
        // k is block size and d is number of
        // rotations in every block.
        var k = 3, d = 2;
        head = rotateByBlocks(head, k, d);
        document.write(
        "<br/>Rotated by blocks Linked list <br/>"
        );
        printList(head);
 
// This code contributed by gauravrajput1
 

输出：

Given linked list 
1 2 3 4 5 6 7 8 9 
Rotated by blocks Linked list 
2 3 1 5 6 4 8 9 7

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