#include<stdio.h>#include<stdlib.h>#include<time.h>#define OK 1#define ERROR 0#define TRUE 1#define FALSE 0typedef int status;typedef int elemtype;typedef struct node{  elemtype data;  int freq;  struct node * next;  struct node * prior;}node;typedef struct node* dlinklist;status visit(elemtype c){  printf("%d ",c);}/*雙向鏈表初始化*/status initdlinklist(dlinklist * head,dlinklist * tail){  (*head)=(dlinklist)malloc(sizeof(node));  (*tail)=(dlinklist)malloc(sizeof(node));  if(!(*head)||!(*tail))    return ERROR;  /*這一步很關鍵*/   (*head)->prior=NULL;  (*tail)->next=NULL;  (*head)->freq=0;  (*tail)->freq=0;   /*鏈表為空時讓頭指向尾*/  (*head)->next=(*tail);  (*tail)->prior=(*head);}/*判定是否為空*/status emptylinklist(dlinklist head,dlinklist tail){  if(head->next==tail)    return TRUE;  else    return FALSE;} /*尾插法創建鏈表*/ status createdlinklist(dlinklist head,dlinklist tail,elemtype data){  dlinklist pmove=head,qmove=tail,pinsert;  pinsert=(dlinklist)malloc(sizeof(node));  if(!pinsert)    return ERROR;  else{    pinsert->data=data;    pinsert->prior=pmove;    pinsert->next=pmove->next;    pmove->next->prior=pinsert;    pmove->next=pinsert;  }}/*正序打印鏈表*/ status traverselist(dlinklist head,dlinklist tail){  dlinklist pmove=head->next;  while(pmove!=tail){    visit(pmove->data);    pmove=pmove->next;  }  printf("/n");}status traverselist2(dlinklist head,dlinklist tail){  dlinklist pmove=head->next;  while(pmove!=tail){    visit(pmove->freq);    pmove=pmove->next;  }  printf("/n");}/*在鏈表頭插入元素*/status inserthead(dlinklist head,dlinklist tail,elemtype data){  dlinklist pinsert;  pinsert=(dlinklist)malloc(sizeof(node));  pinsert->data=data;  pinsert->next=NULL;  pinsert->prior=NULL;  tail->prior->next=pinsert;  pinsert->prior=tail->prior;  pinsert->next=tail;  tail->prior=pinsert;  return OK;}/*按使用頻次排序*/ status locateorder(dlinklist head,dlinklist tail,elemtype data){  dlinklist pmove=head->next,qmove;  while(pmove!=tail&&pmove->data!=data)    pmove=pmove->next;  if(pmove==tail){    printf("未找到/n");    return ERROR;  }  else{    pmove->freq++;    qmove=pmove->prior;    while(qmove!=head&&qmove->freq<pmove->freq)//向前尋找比pmove->freq大的qmove->freq       qmove=qmove->prior;    if(qmove->next!=pmove){//如果找到的qmove和pmove不是直接的前驅后繼關系      pmove->next->prior=pmove->prior;      pmove->prior->next=pmove->next;//將pmove取下      pmove->prior=qmove;      pmove->next=qmove->next;      qmove->next->prior=pmove;      qmove->next=pmove;//插到qmove之后    }  }}int main(void){  dlinklist head,tail,pmove=head;  int i=0;  initdlinklist(&head,&tail);  for(i=0;i<10;i++)    inserthead(head,tail,i);  printf("未經過排序的鏈表為/n");  traverselist(head,tail);  printf("在按使用頻率排序后的鏈表為:/n");   locateorder(head,tail,5);  for(int i=0;i<3;i++){    locateorder(head,tail,6);  }  traverselist(head,tail);  printf("各元素使用頻率為/n");  traverselist2(head,tail);}