用单链表实现双向队列

来源：互联网发布：js数组删除空元素编辑：程序博客网时间：2024/06/05 05:28

纯为了练习码代码，熟悉一下链表的使用

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

#define DQSIZE 10
#define LEFT 0          //左边
#define RIGHT 1      //右边

typedef struct Element{
   int key;
   /*other field*/
} Element;

typedef struct Node{
   struct Node * next;
   Element elem;
} Node;

typedef struct Deque{
   int qsize;
   Node * left;
   Node * right;
} Deque;

int initDq(Deque * dq);
int addDq(Deque *dq, const Element * e, int flag); //flag = 0 左边插入， flag = 1, 右边插入
int deleteDq(Deque * dq, Element * e, int flag);//flag = 0 左边删除， flag = 1, 右边删除
int destoryDq(Deque * dq);
int isFull(Deque *dq);
int isEmpty(Deque *dq);

int main(void)
{
   Deque q;
   int i;
   Element e;

   initDq(&q);
   printf("left in: \n");
   for(i = 0; i < DQSIZE + 1; i++)
   {
       e.key = 2 * i + 1;
       if(isFull(&q))
       {
           printf("deque is full.\n");
           break;
       }
       addDq(&q, &e, LEFT);
       printf("%d\t", e.key);
       if(i % 5 == 4)
           printf("\n");
   }
   printf("right out: \n");
   for(i = 0; i < DQSIZE + 1; i++)
   {
       e.key = 2 * i + 1;
       if(isEmpty(&q))
       {
           printf("deque is empty.\n");
           break;
       }
       deleteDq(&q, &e, RIGHT);
       printf("%d\t", e.key);
       if(i % 5 == 4)
           printf("\n");
   }
   printf("right in: \n");
   for(i = 0; i < DQSIZE + 1; i++)
   {
       e.key = 2 * i + 1;
       if(isFull(&q))
       {
           printf("deque is full.\n");
           break;
       }
       addDq(&q, &e, RIGHT);
       printf("%d\t", e.key);
       if(i % 5 == 4)
           printf("\n");
   }
   printf("left out: \n");
   for(i = 0; i < DQSIZE + 1; i++)
   {
       e.key = 2 * i + 1;
       if(isEmpty(&q))
       {
           printf("deque is empty.\n");
           break;
       }
       deleteDq(&q, &e, LEFT);
       printf("%d\t", e.key);
       if(i % 5 == 4)
           printf("\n");
   }
   printf("left in: \n");
   for(i = 0; i < DQSIZE + 1; i++)
   {
       e.key = 2 * i + 1;
       if(isFull(&q))
       {
           printf("deque is full.\n");
           break;
       }
       addDq(&q, &e, LEFT);
       printf("%d\t", e.key);
       if(i % 5 == 4)
           printf("\n");
   }
   printf("left out: \n");
   for(i = 0; i < DQSIZE + 1; i++)
   {
       e.key = 2 * i + 1;
       if(isEmpty(&q))
       {
           printf("deque is empty.\n");
           break;
       }
       deleteDq(&q, &e, LEFT);
       printf("%d\t", e.key);
       if(i % 5 == 4)
           printf("\n");
   }
   destoryDq(&q);

   return 0;
}

int initDq(Deque * dq)
{
   if(NULL == dq)
       return -1;

   dq->qsize = 0;
   dq->left = dq->right = NULL;
   return 1;
}

int addDq(Deque *dq, const Element * e, int flag)
{
   Node * pnode;

   if(NULL == dq || e == NULL ||(flag != 0 && flag != 1))
   {
       printf("addDq parameter error.\n");
       return -1;
   }

   if(isFull(dq))
   {
       return 0;
   }

   if((pnode = (Node *)malloc(sizeof(Node))) == NULL )
       return 0;

   pnode->elem = *e;
   pnode->next = NULL;

   if(isEmpty(dq))
   {
       dq->left = dq->right = pnode;
       dq->qsize++;
       return 1;
   }

   if(flag == 0)//left
   {
       pnode->next = dq->left;
       dq->left = pnode;
   }
   else
   {
       dq->right->next = pnode;
       dq->right = pnode;
   }
   dq->qsize++;

   return 1;
}

int deleteDq(Deque * dq, Element * e, int flag)
{
   Node * pnode;

   if(NULL == dq || NULL == e ||(flag != 0 && flag != 1))
   {
       printf("addDq parameter error.\n");
       return -1;
   }

   if(isEmpty(dq))
       return 0;

   if(flag == 0)
   {
       if(dq->left->next == NULL)//只有一个节点
       {
           *e = dq->left->elem;
           free(dq->left);
           dq->left = dq->right = NULL;
       }
       else
       {
           *e = dq->left->elem;
           pnode = dq->left;
           dq->left = dq->left->next;
           free(pnode);
       }
       dq->qsize--;
       return 1;
   }
   else
   {
       if(dq->left->next == NULL)//只有一个节点
       {
           *e = dq->left->elem;
           free(dq->left);
           dq->left = dq->right = NULL;
       }
       else
       {
           pnode = dq->left;
           while(pnode->next != NULL)//寻找指向rear的指针
           {
               if(pnode->next->next == NULL)
               {
                   break;
               }
               pnode = pnode->next;
           }
           *e = dq->right->elem;
           free(dq->right);
           pnode->next = NULL;
           dq->right = pnode;
       }
       dq->qsize--;
       return 1;
   }

}

int destoryDq(Deque * dq)
{
   Element temp;
   if(dq == NULL)
       return 1;
   while(!isEmpty(dq))
   {
       deleteDq(dq, &temp, LEFT);
   }
   return 1;
}
int isFull(Deque *dq)
{
   if(dq->qsize == DQSIZE)
       return 1;
   return 0;
}

int isEmpty(Deque *dq)
{
   if(dq->qsize == 0)
       return 1;
   return 0;
}

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