有序双循环链表的插入 代码(C)



有序双循环链表的插入, 须要找到插入位置, 能够採用, 两个指针, 一个在前, 一个在后.

保证前面的小于等于插入值, 后面的大于等于插入值.


特殊情况, 首尾插入(大于或小于整个链表)或单节点, 推断条件为后指针指向首节点. 则须要直接插入.

插入链表头, 须要调整链表头节点.


代码22行.


代码:

/*
 * main.cpp
 *
 *  Created on: 2014.9.18
 *      Author: Spike
 */

/*eclipse cdt, gcc 4.8.1*/

#include <stdio.h>
#include <stdlib.h>

using namespace std;

struct ListNode {
  ListNode (int v) {
    value = v;
    prev = NULL;
    next = NULL;
  }
  int value;
  ListNode* prev;
  ListNode* next;
};

ListNode* CreateLists() {
  ListNode* head = new ListNode(0);
  ListNode* node1 = new ListNode(1);
  ListNode* node2 = new ListNode(2);
  ListNode* node4 = new ListNode(4);
  ListNode* node5 = new ListNode(5);

  head->prev = node5;
  head->next = node1;

  node1->prev = head;
  node1->next = node2;

  node2->prev = node1;
  node2->next = node4;

  node4->prev = node2;
  node4->next = node5;

  node5->prev = node4;
  node5->next = head;

  return head;
}

ListNode* CreateLists2() {
  ListNode* head = new ListNode(0);

  head->prev = head;
  head->next = head;

  return head;
}

void Print(ListNode* head) {
  ListNode* node = head;
  printf("%d ", node->value);
  node = node->next;
  while (node != head) {
    printf("%d ", node->value);
    node = node->next;
  }
  printf("\n");
}

ListNode* InsertNode(ListNode* head, ListNode* node) {
  if (head == NULL || node == NULL)
    return head;
  ListNode* prevNode = head;
  ListNode* nextNode = head->next;
  while(1) {
    if ((prevNode->value < node->value &&
        nextNode->value >= node->value)
        || (nextNode == head))
    {
      prevNode->next = node;
      node->prev = prevNode;
      nextNode->prev = node;
      node->next = nextNode;
      if (node->value < head->value) {
        head = node;
      }
      break;
    }
    prevNode = prevNode->next;
    nextNode = prevNode->next;
  }
  return head;
}

int main (void)
{
  ListNode* head = CreateLists();
  Print(head);
  ListNode* node = new ListNode(3);
  ListNode* newList = InsertNode(head, node);
  Print(newList);
  return 0;
}




输出:

0 1 2 4 5 
0 1 2 3 4 5



编程算法 - 有序双循环链表的插入 代码(C)_#include