有两个双向链表，空白头结点为：ListA和ListB，要求删除这两个链表中关键字相同的结点, C语言实现，结点结构如下：

 完整代码：

/*功能：删除两个双向链表(都带空白头结点)中值(key)相同的结点，规定header.front始终指向尾结点名词定义：空白头结点：该结点不作为真正保存值的结点；其front成员规定指向尾结点, next指向第一个非空白结点；当该链表无结点时，规定其front和next都为NULL.头结点：	链表的第一个非空白头结点(第一个元素)尾结点：	链表的最后一个非空白结点
*/#include <stdio.h>
#include <stdlib.h>
#include <string.h>struct node								// 双向链表结点
{int key;struct node *front, *next;
};/*功能：	创建双向链表(尾插法：新创建的结点放在链表尾部)返回值：1-创建成功，0-创建失败header:	创建的双向链表的头指针n:		待创建的结点个数
*/
int createLinklist(struct node *header, int n)
{int v;struct node *p = NULL;printf("请输入%d个整数：\n", n);while(n-- > 0){scanf("%d", &v);p = malloc(sizeof(struct node));if(p){if(header->next == NULL)header->next = p;		// 设置链表头指针else{header->front->next = p;p->front = header->front;}p->key = v;p->next = header->next;		// 新结点的next指向第一个结点header->next->front = p;	// 结点的front指向新结点(作为最后一个结点)header->front = p;			// header->front始终指向最后一个结点}elsereturn 0;					// 创建链表失败}return 1;							// 创建链表成功
}// 输出双向链表中的值
void displayLinklist(struct node *header)
{struct node *p = header->next;printf("header.front = 0x%X, header.next = 0x%X\n", header->front, header->next);if(NULL != p){do{printf("[p = 0x%X]\tdata = %d, front = 0x%X, next = 0x%X\n", p, p->key, p->front, p->next);p = p->next;}while(p != header->next);printf("\n");}	
}// 删除双向链表中所有结点并释放空间(头删法)
void FreeLinklist(struct node *header)
{struct node *p;while(header->next){p = header->next;				// p指向待删结点if(p == header->front)			// 待删除的是尾结点{header->front = header->next = NULL;}else{header->front->next = p->next;p->next->front = header->front;header->next = p->next;}free(p);}
}/*功能：		删除双向链表(头指针pHeader)中值与key相同的结点，从结点*pStart开始向后搜索返回值：	如果从双向链表中删除了值为指定key的结点，返回1，否则返回0pHeader:	双向链表空白头指针pStart:		从*pStart开始向后搜索，删除值与key相同的结点，直到遇到pHeader->nextkey:		待删结点关键字注意：		调用此函数时，输入参数pHeader==*pStart，程序将会出错
*/
int removeNode(struct node *pHeader, struct node **pStart, int key)
{struct node *p, *temp;int del = 0;p = *pStart;*pStart = NULL;while(p){if(p->key == key){del = 1;temp = p;									// temp指向待删结点if(pHeader->next == p)						// 删除头结点{if(pHeader->front == pHeader->next)		// 待删结点是链表的唯一结点pHeader->front = pHeader->next = NULL;else{	pHeader->front->next = p->next;p->next->front = pHeader->front;	// 尾结点的next指向新的头结点pHeader->next = p->next;}p = pHeader->next;						// p指向新的头结点}else{p->front->next = p->next;p->next->front = p->front;if(p == pHeader->front)					// 待删除的是尾结点pHeader->front = p->front;			// pHeader->front指向新的尾结点p = p->next;							// p指向被删除结点的后继结点}free(temp);}else{if(*pStart == NULL)*pStart = p;p = p->next;}if(*pStart && p == pHeader->next)break;}return del;
}// 删除两个链表中值相同的结点
void removeEqualNodes(struct node *pHeadA, struct node *pHeadB)
{struct node *p1, *p2;int del = 0;p1 = pHeadA->next;while(p1){p2 = pHeadB->next;if((del = removeNode(pHeadB, &p2, p1->key)) == 1){removeNode(pHeadA, &p1, p1->key);}elsep1 = p1->next;if(pHeadB->next == NULL || pHeadA->next == NULL || (del == 0 && p1 == pHeadA->next))break;}
}int main(int argc, char *argv[])
{struct node listA, listB;				// 定义两个双向链表的空白头结点int n1, n2;								// 保存待创建的链表结点个数if(argc < 3){printf("Usage: %s <n1> <n2>\n", argv[0]);return 1;}n1 = atoi(argv[1]);n2 = atoi(argv[2]);listA.front = listA.next = NULL;listB.front = listB.next = NULL;createLinklist(&listA, n1);				// 创建双向链表createLinklist(&listB, n2);printf("Before remove:\n");displayLinklist(&listA);				// 显示双向链表内容displayLinklist(&listB);removeEqualNodes(&listA, &listB);		// 删除两个链表中值相同的结点printf("\nAfter remove:\n");displayLinklist(&listA);displayLinklist(&listB);FreeLinklist(&listA);					// 释放空间FreeLinklist(&listB);return 0;
}

运行结果：

E:\Program\VC\del\Debug>del.exe 2 4
请输入2个整数：
14 25
请输入4个整数：
14 25
63 66
Before remove:
header.front = 0x3807E0, header.next = 0x3807A8
[p = 0x3807A8]  data = 14, front = 0x3807E0, next = 0x3807E0
[p = 0x3807E0]  data = 25, front = 0x3807A8, next = 0x3807A8header.front = 0x3808C0, header.next = 0x380818
[p = 0x380818]  data = 14, front = 0x3808C0, next = 0x380850
[p = 0x380850]  data = 25, front = 0x380818, next = 0x380888
[p = 0x380888]  data = 63, front = 0x380850, next = 0x3808C0
[p = 0x3808C0]  data = 66, front = 0x380888, next = 0x380818After remove:
header.front = 0x0, header.next = 0x0
header.front = 0x3808C0, header.next = 0x380888
[p = 0x380888]  data = 63, front = 0x3808C0, next = 0x3808C0
[p = 0x3808C0]  data = 66, front = 0x380888, next = 0x380888E:\Program\VC\del\Debug>del.exe 2 4
请输入2个整数：
14 25
请输入4个整数：
12 23 21 54
Before remove:
header.front = 0x3807E0, header.next = 0x3807A8
[p = 0x3807A8]  data = 14, front = 0x3807E0, next = 0x3807E0
[p = 0x3807E0]  data = 25, front = 0x3807A8, next = 0x3807A8header.front = 0x3808C0, header.next = 0x380818
[p = 0x380818]  data = 12, front = 0x3808C0, next = 0x380850
[p = 0x380850]  data = 23, front = 0x380818, next = 0x380888
[p = 0x380888]  data = 21, front = 0x380850, next = 0x3808C0
[p = 0x3808C0]  data = 54, front = 0x380888, next = 0x380818After remove:
header.front = 0x3807E0, header.next = 0x3807A8
[p = 0x3807A8]  data = 14, front = 0x3807E0, next = 0x3807E0
[p = 0x3807E0]  data = 25, front = 0x3807A8, next = 0x3807A8header.front = 0x3808C0, header.next = 0x380818
[p = 0x380818]  data = 12, front = 0x3808C0, next = 0x380850
[p = 0x380850]  data = 23, front = 0x380818, next = 0x380888
[p = 0x380888]  data = 21, front = 0x380850, next = 0x3808C0
[p = 0x3808C0]  data = 54, front = 0x380888, next = 0x380818E:\Program\VC\del\Debug>del.exe 0 0
请输入0个整数：
请输入0个整数：
Before remove:
header.front = 0x0, header.next = 0x0
header.front = 0x0, header.next = 0x0After remove:
header.front = 0x0, header.next = 0x0
header.front = 0x0, header.next = 0x0E:\Program\VC\del\Debug>del.exe 0 2
请输入0个整数：
请输入2个整数：
12 54
Before remove:
header.front = 0x0, header.next = 0x0
header.front = 0x3807E0, header.next = 0x3807A8
[p = 0x3807A8]  data = 12, front = 0x3807E0, next = 0x3807E0
[p = 0x3807E0]  data = 54, front = 0x3807A8, next = 0x3807A8After remove:
header.front = 0x0, header.next = 0x0
header.front = 0x3807E0, header.next = 0x3807A8
[p = 0x3807A8]  data = 12, front = 0x3807E0, next = 0x3807E0
[p = 0x3807E0]  data = 54, front = 0x3807A8, next = 0x3807A8E:\Program\VC\del\Debug>del.exe 2 0
请输入2个整数：
14 25
请输入0个整数：
Before remove:
header.front = 0x3807E0, header.next = 0x3807A8
[p = 0x3807A8]  data = 14, front = 0x3807E0, next = 0x3807E0
[p = 0x3807E0]  data = 25, front = 0x3807A8, next = 0x3807A8header.front = 0x0, header.next = 0x0After remove:
header.front = 0x3807E0, header.next = 0x3807A8
[p = 0x3807A8]  data = 14, front = 0x3807E0, next = 0x3807E0
[p = 0x3807E0]  data = 25, front = 0x3807A8, next = 0x3807A8header.front = 0x0, header.next = 0x0E:\Program\VC\del\Debug>del.exe 1 1
请输入1个整数：
25 25
请输入1个整数：
Before remove:
header.front = 0x3807A8, header.next = 0x3807A8
[p = 0x3807A8]  data = 25, front = 0x3807A8, next = 0x3807A8header.front = 0x3807E0, header.next = 0x3807E0
[p = 0x3807E0]  data = 25, front = 0x3807E0, next = 0x3807E0After remove:
header.front = 0x0, header.next = 0x0
header.front = 0x0, header.next = 0x0E:\Program\VC\del\Debug>del.exe 5 6
请输入5个整数：
14 25 63 47 58 14
请输入6个整数：
25 36 47 55 25
Before remove:
header.front = 0x380888, header.next = 0x3807A8
[p = 0x3807A8]  data = 14, front = 0x380888, next = 0x3807E0
[p = 0x3807E0]  data = 25, front = 0x3807A8, next = 0x380818
[p = 0x380818]  data = 63, front = 0x3807E0, next = 0x380850
[p = 0x380850]  data = 47, front = 0x380818, next = 0x380888
[p = 0x380888]  data = 58, front = 0x380850, next = 0x3807A8header.front = 0x3809D8, header.next = 0x3808C0
[p = 0x3808C0]  data = 14, front = 0x3809D8, next = 0x3808F8
[p = 0x3808F8]  data = 25, front = 0x3808C0, next = 0x380930
[p = 0x380930]  data = 36, front = 0x3808F8, next = 0x380968
[p = 0x380968]  data = 47, front = 0x380930, next = 0x3809A0
[p = 0x3809A0]  data = 55, front = 0x380968, next = 0x3809D8
[p = 0x3809D8]  data = 25, front = 0x3809A0, next = 0x3808C0After remove:
header.front = 0x380888, header.next = 0x380818
[p = 0x380818]  data = 63, front = 0x380888, next = 0x380888
[p = 0x380888]  data = 58, front = 0x380818, next = 0x380818header.front = 0x3809A0, header.next = 0x380930
[p = 0x380930]  data = 36, front = 0x3809A0, next = 0x3809A0
[p = 0x3809A0]  data = 55, front = 0x380930, next = 0x380930E:\Program\VC\del\Debug>