数据结构之双端队列

来源：互联网发布：禁止域用户安装软件编辑：程序博客网时间：2024/06/04 18:19

摘要：有时候一个队列可能需要能从两端进出，这时候称呼它为双端队列。具体思路很简单，从代码可以直接看出来。

#include "stdafx.h"#include "malloc.h"#include "stdlib.h"typedef struct DequeueRecord *queue;struct DequeueRecord{    int Capcity;    int size;    int Front ;    int Rear;    int * Array;};queue Create(int MaxElements){    queue Q;    Q = (queue)malloc(sizeof(DequeueRecord));    Q->Capcity = MaxElements;    Q->Array = (int *)malloc(sizeof(int )*MaxElements);    Q->size = 0;    Q->Front = -1;    Q->Rear = Q->Capcity;    return Q;}void Inject(queue Q,int x)//后端入队{    if (Q->size == Q->Capcity)    {        puts("error: it is impossible to insert an element inot a full dequeue");        return;    }    //插入到尾端    Q->Array[--Q->Rear] = x;    Q->size++;}void Push(queue Q,int x)//前端入队{if (Q->size == Q->Capcity)    {        puts("error: it is impossible to insert an element inot a full dequeue");        return;    }//插入前端Q->Array[++Q->Front] = x;Q->size++;} int Eject(queue Q)//后端出队{    if (Q->size == 0 )    {        puts("it is impossible to delete an element from a empty dequeue");        return (-1);    }    //删除后端    Q->Rear = (Q->Capcity + Q->Rear)%Q->Capcity;    Q->size -- ;    return Q->Array[Q->Rear++];}int Pop(queue Q)//前端出队{    if (Q->size == 0 )    {        puts("it is impossible to delete an element from a empty dequeue");        return (-1);    }    //删除前端    Q->Front = (Q->Capcity + Q->Front)%Q->Capcity;    Q->size -- ;    return Q->Array[Q->Front--];}int _tmain(int argc, _TCHAR* argv[]){    int i = 0;    queue Q;    Q = Create(20);    while(i++<5)        Push(Q,i);    while(i-->1)       Inject(Q,i);       while(i++ <9)           printf("%d ",Pop(Q));       puts("\n");       i = 0;       while(i++<3)           printf("%d",Eject(Q));    return 0;}

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