【数据结构】离散事件模拟

#include "book3_6.h"
//
#define CloseTime 600
EventList ev; //事件表
Event     en; //事件
LinkQueue  q[5]; //4个客户队列
QElemType customer; //客户记录
int TotalTime,CustomerNum; //累积客户逗留时间，客户数

int Minimum(LinkQueue q[])
{
int l[5];
for (int i=1; i<=4; i++)
{
l[i]=q[i].rear - q[i].front;
}
int a = l[1]>l[2]?2:1;
int b = l[3]>l[4]?4:3;
return l[a]>l[b]?b:a;
}

void OpenForDay()
{
//初始化操作
TotalTime = 0; CustomerNum = 0; //初始化累积时间和客户数
ListCreate_L(ev);               //初始化事件链表为空表
en.OccurTime = 0; en.NType = 0; //设定第一个客户到达事件
OrderInsert(ev,en,cmp);         //插入事件表
for(int i=1;i<=4;i++) InitQueue_L(q[i]); //置空队列
}//OpenForDay

void CustomerArrived()
{
//处理客户到达事件  en.NType = 0;

int durtime, intertime;
ElemType tmp;
QElemType Qtmp;
++CustomerNum;

durtime = 1+(int)(30.0*rand()/(RAND_MAX+1.0)); //处理时间
intertime = 1+(int)(5.0*rand()/(RAND_MAX+1.0)); //下一客户到达时间间隔
//printf("durtime:%d\ intertime:%d\n",durtime,intertime);
int t = en.OccurTime + intertime;  //下一客户到达时间
if(t<CloseTime) //银行未关门 插入事件表
{
tmp.OccurTime = t;
tmp.NType = 0;
OrderInsert(ev,tmp,cmp);
}
int i = Minimum(q);
Qtmp.ArrivalTime = en.OccurTime;
Qtmp.Duration = durtime;
EnQueue_L(q[i],Qtmp); //将当前到来的客户插入队列
if(QueueLength_L(q[i]) == 1)
{
tmp.OccurTime = en.OccurTime+durtime;
tmp.NType = i;
OrderInsert(ev,tmp,cmp); //若队列长度为1 则插入一个离开事件 因为只有前一个人离开了 后面的人才能离开
}

}

void CustomerDeparture()
{
//处理客户离开事件 ，en.Type>0;
ElemType tmp;
int i = en.NType;  DeQueue_L(q[i],customer); //删除第i队列的排头客户
//printf("time:%d\n",en.OccurTime - customer.ArrivalTime);
TotalTime += en.OccurTime - customer.ArrivalTime;
if(!QueueEmpty_L(q[i]))
{
GetHeadQueue_L(q[i],customer);
tmp.NType = i;
tmp.OccurTime = en.OccurTime + customer.Duration;
OrderInsert(ev,(tmp),cmp);
}
}

void Bank_Simulation()
{
ElemType tmp;
OpenForDay();
while(!ListEmpty_L(ev))
{
ListDeleteFirst_L(ev, tmp);
en = tmp;
if(en.NType == 0)
CustomerArrived();
else
CustomerDeparture();
}

printf("The Average Time is %f\n",(float)TotalTime/CustomerNum);
}

void main()
{
srand((int)time(0));
for(int i=0; i<10; i++)
{
Bank_Simulation();
}
getchar();

}

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

typedef int Status;
const int TRUE=1;
const int FALSE=0;
const int OK=1;
const int ERROR=0;
const int INFEASIBLE=-1;
const int overflow=-2;
const int STACK_INIT_SIZE=100;
const int STACKINCREMENT=10;

typedef struct{
int ArrivalTime;
int Duration;
}QElemType;

//线性链表
typedef struct{
int OccurTime;
int NType;
}Event, ElemType; //元素类型

typedef struct LNode{
ElemType data;
struct LNode *next;
}LNode, *LinkList;    //线性链表结点

typedef LinkList EventList;

int cmp(int a , int b)
{
if(a>b)
return 1;
else if(a<b)
return -1;
else
return 0;
}

//按OccurTime由小到大的顺序排列 相同的则先进来的排前面
Status OrderInsert( LinkList &L, ElemType e, int(* compare)(int, int))
{
ElemType tmp;
LinkList s;
LinkList p = L;
if(p->next==NULL)  //没有元素则直接插入
{
s = (LinkList)malloc(sizeof(LNode));
s->data = e; s->next = p->next;
p->next = s;
}
else
{
while(compare(e.OccurTime,p->next->data.OccurTime) != -1)
{
p = p->next;
if(p->next == NULL)
{
s = (LinkList)malloc(sizeof(LNode));
s->data = e; s->next = p->next;
p->next = s;
return OK;
}
}
s = (LinkList)malloc(sizeof(LNode));
s->data = e; s->next = p->next;
p->next = s;

}

return OK;

}

//删除链表的最后一个元素
Status ListDeleteLast_L(LinkList &L, ElemType &e)
{
LinkList s;
LinkList p = L;
while(p->next->next != NULL)
{
p = p->next;
}
s = p;
e = p->next->data;
free(p->next);
s->next = NULL;

return OK;
}

//创建一个新的空链表
Status ListCreate_L(LinkList &L)
{
if(L == NULL)
{
L = (LinkList)malloc(sizeof(LNode));
L->next = NULL;
return OK;
}
else
return ERROR;
}

//销毁一个链表
Status ListDestroy_L(LinkList &L)
{
LinkList p=L, s;
while(p->next != NULL)
{
s = p; p = p->next;  free(s);
}
return OK;
}

bool ListEmpty_L(LinkList L)
{
if(L->next==NULL)
return true;
else
return false;
}

//删除链表的第一个元素
Status ListDeleteFirst_L(LinkList &L, ElemType &e)
{
LinkList s;
LinkList p = L;

s = p;
p = p->next;
e = p->data;
s->next = p->next;
free(p);

return OK;
}

//循环队列
#define MAXQSIZE 100
typedef struct{
QElemType *base;
int front;
int rear;
}SqQueue;

Status InitQueue(SqQueue &Q)
{
//构造一个空队列Q
Q.base = (QElemType * ) malloc (MAXQSIZE * sizeof(QElemType));
if(!Q.base) exit(overflow);
Q.front = Q.rear = 0;
return OK;
}

int QueueLength(SqQueue Q)
{
//返回Q的元素个数，即队列的长度
return (Q.rear - Q.front + MAXQSIZE) % MAXQSIZE;
}

Status EnQueue(SqQueue &Q, QElemType e)
{
//插入元素e为新的队尾元素
if((Q.rear +1)%MAXQSIZE == Q.front) return ERROR; //队列满
Q.base[Q.rear] = e;
Q.rear = (Q.rear +1) % MAXQSIZE;
return OK;
}

Status DeQueue(SqQueue &Q, QElemType &e)
{
//若队列不空，则删除Q的队头元素, 用e返回其值，并返回OK;
//否则返回 ERROR
if(Q.front == Q.rear) return ERROR;
e = Q.base[Q.front];
Q.front = (Q.front + 1)%MAXQSIZE;
return OK;
}

Status DestroyQueue(SqQueue &Q)
{
//删除队列Q
if(Q.base != NULL)
{
free(Q.base);
Q.front = Q.rear =0;
return OK;
}
return ERROR;
}

Status GetHeadQueue(SqQueue &Q, QElemType &e)
{
//获取队列队头的元素
e = Q.base[Q.front];
return OK;
}

//链队列
typedef struct QNode{
QElemType data;
struct QNode *next;
}QNode, *QueuePtr;

typedef struct{
QueuePtr front; //队头指针
QueuePtr rear;  //队尾指针
}LinkQueue;

Status InitQueue_L(LinkQueue &Q)
{
//构造一个空队列Q
Q.front = Q.rear = (QueuePtr)malloc(sizeof(QNode));
if(Q.front==NULL) exit(overflow);
Q.front->next=NULL;
return OK;
}

Status DestroyQueue_L(LinkQueue &Q)
{
//销毁一个队列
while(Q.front!=NULL)
{
Q.rear = Q.front->next;
free(Q.front);
Q.front = Q.rear;
}
return OK;
}

Status EnQueue_L(LinkQueue &Q, QElemType e){
//插入元素e为Q的新的队尾元素
QueuePtr p = (QueuePtr)malloc(sizeof(QNode));
if(!p) exit(overflow);
p->data = e;  p->next =NULL;
Q.rear->next = p;
Q.rear  = p;
return OK;
}

Status DeQueue_L(LinkQueue &Q, QElemType &e)
{
//若队列不空 删除Q的队头元素，用e返回其值，并返回OK
//否则返回ERROR
QueuePtr p;
if(Q.rear == Q.front) return ERROR;
p = Q.front->next;
e = p->data;
Q.front->next = p->next;
if(Q.rear == p) Q.rear = Q.front;
free(p);
return OK;
}

int QueueLength_L(LinkQueue Q)
{
//返回Q的元素个数，即队列的长度
if(Q.front == Q.rear)
{
return 0;
}
QueuePtr p = Q.front;
int i = 1;
while(p->next != Q.rear)
{
i++;
p=p->next;
}
return i;
}

bool QueueEmpty_L(LinkQueue Q)
{
if(Q.rear == Q.front)
return true;
else
return false;
}

Status GetHeadQueue_L(LinkQueue Q, QElemType &e)
{
e = Q.front->next->data;
return OK;
}

主程序和头文件如上。

注意：

1.srand()只初始化一次 否则会产生相同的随机数；

2.模拟的过程要符合日常的生活 即当一个客户到来时产生下一个客户到来的事件 队头客户离开时产生新队头客户的离开事件 原本队列没有人时 新加入客户时要产生客户离开事件。每个客户等待时间长度的计算是通过离开事件的时间减去到达的时间，而不是自己加出来的。