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题目源自严奶奶的数据结构题集(c语言版) p19页的Algo2.38
ps:严奶奶的书默认都是带有头结点的。
设有一个双向循环链表,每个结点中除有prior,data,next三个域以外,还增设了一个访问频度域freq。在链表被启用之前,freq域的值均被初始化为零,而每当对链表进行一次Locate(L,x)的操作之后,被访问的结点(即元素值等于x的结点)中的频度域freq的值便增加1,同时调整链表中结点之间的次序,使其按照访问频度非递增的次序顺序排列,一遍始终保持被频繁访问的结点总是靠近表头结点。试编写符合上述要求的Locate(L,x)操作的算法。
思路:Locate到等于x的点,freq自增1,由于是递减排列,p指针向前寻找到第一个比x的freq大或者相等的结点,插在p后面
代码
头文件
//Status.h
#pragma once
#define TRUE 1
#define OK 1
#define FALSE 0
#define ERROR 0
#define OVERFLOW -1
typedef int Status;
//DuCycle_LinkList.h
#pragma once
#include <stdio.h>
#include "Status.h"
typedef int ElemType;
typedef struct DuCycle_Lnode {
ElemType data;
struct DuCycle_Lnode * next;
struct DuCycle_Lnode * prior;
int freq;
}DuCycle_Lnode,* DuCycle_List;
Status Init(DuCycle_List &L);
Status SelfLearning_Locate(DuCycle_List &L, ElemType e);//Algo2.38
Status Make_List(DuCycle_List &L);
Status Trav_DuCycle_List(DuCycle_List L);
函数文件
//fun.cpp
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include "DuCycle_LinkList.h"
Status Init(DuCycle_List &L)
{
L = (DuCycle_Lnode *)malloc(sizeof(DuCycle_Lnode));
if (!L) exit(OVERFLOW);
L->freq = 0;
L->prior = L->next = NULL;
L->data = NULL;
return OK;
}//Init
Status Trav_DuCycle_List(DuCycle_List L)
{
DuCycle_Lnode * p;
p = L->next;
if (L->next == NULL) return ERROR;
while (p != L)
{
printf("%d(%d) ", p->data,p->freq);
p = p->next;
}
/*putchar('\n');
p = L->next;
while (p != L)
{
printf("%d", p->freq);
p = p->next;
}*/
putchar('\n');
return OK;
}//Trav_DuCycle_List
Status SelfLearning_Locate(DuCycle_List &L,ElemType e)//Algo2.38
//自学习的Locate算法,结点中增加freq表示访问的频度
//每次访问将自组所有织结点重新按照freq降序排列
{
DuCycle_Lnode *p, *q;
p = NULL;
q = L->next;
while (q->next!=L&&q->data!=e)
{
q = q->next;
}
if (q->data == e)//发现e
{
q->freq++;
p = q->prior;
while (p!=L&&p->freq<q->freq)//移动p到第一个比e的freq大的结点上,或者头结点
{
p = p->prior;
}
q->next->prior = q->prior;
q->prior->next = q->next;//ditach q
q->next = p->next;//rejoin q
p->next->prior = q;
p->next = q;
q->prior = p;
printf("element found.\n");
return OK;
}
printf("element not found.\n");
return ERROR;//未发现e
}//SelfLearning_Locate
Status Make_List(DuCycle_List &L)
{
int n;
printf("plz input the node you want to add.\n");
scanf("%d", &n);
printf("plz input %d numbers in.\n", n);
for (int i = 0; i < n; i++)
{
ElemType e;
scanf("%d", &e);
DuCycle_Lnode *s= (DuCycle_Lnode *)malloc(sizeof(DuCycle_Lnode));
if (!s) return ERROR;
s->data = e;
s->freq = 0;
if (L->next != NULL)
{
s->next = L->next;
L->next->prior = s;
L->next = s;
s->prior = L;
}
else
{
L->next = s;
L->prior = s;
s->prior = L;
s->next = L;
}
}
printf("List make succeed.\n");
return OK;
}//Make_List
主函数
//main.cpp
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include "DuCycle_LinkList.h"
#include "Status.h"
int main(void)
{
DuCycle_List L;
ElemType e;
int n;
Init(L);
Make_List(L);
Trav_DuCycle_List(L);
printf("input the element you want to locate.(not a number to quit)\n");
while (scanf("%d",&e))
{
SelfLearning_Locate(L, e);
Trav_DuCycle_List(L);
}
system("pause");
return 0;
}
运行结果如下:
第一篇博客,写的不好还请见谅。如果有错误的地方欢迎留言指出 :)