各种基本算法实现小结（一）—— 链 表

#include <stdio.h>
struct _node
{
    int data;
    struct _node *next;
};
typedef struct _node list;
void display(list *l)
{
    list *p;
    p=l;
    while(p->next)
    {
        printf("%5d", p->next->data);
        p=p->next;
    }
}
void main()
{
    int i, n;
    list *h, *p, *s;
    printf("Enter num n:");
    scanf("%d", &n);
    h=(list*)malloc(sizeof(list));
    h->data=-1;
    h->next=NULL;
    s=p=h;
    for(i=n;i>0;i--)
    {
        p=(list*)malloc(sizeof(list));
        scanf("%d", &(p->data));
        p->next=h->next;
        h->next=p;
        h=h->next;
    }
    display(s);
    getch();
}

#include <stdio.h>
#include <malloc.h>
#include <stdlib.h>
struct _node
{
    int data;
    struct _node *next;
};
typedef struct _node node, *plist;
plist init_list()
{
    plist pl;
    pl=(plist)malloc(sizeof(node));
    if(NULL==pl)
    {
        printf("init list,  malloc is fail.../n");
        return NULL;
    }
    pl->data=-1;
    pl->next=NULL;
    return pl;
}
int isempty_list(plist pl)
{
    if(NULL==pl || NULL!=pl->next)
        return 1;
    else
        return 0;
}
plist clear_list(plist pl)
{
    pl=NULL;
    return pl;
}
void destroy_list(plist pl)
{
    plist p, s;
    
    p=pl->next;
    while(p)
    {
        s=p;
        p=p->next;
        free(s);     
    }
    
    pl=NULL;
}
void insert_item(plist pl, int i, int e)
{
    int j=1;
    plist p, s;
    p=pl;
    while(p && j<i)
    {
        p=p->next;
        j++;
    }
    if(!p || j>i)  /* >len or <1  */
        printf("Insert fail.../n");
    s=(plist)malloc(sizeof(node));
    s->data=e;
    s->next=p->next;
    p->next=s;
}
void display(plist pl)
{
    plist p;
    p=pl->next;
    while(pl && p)
    {
        printf("%5d", p->data);
        p=p->next;
    }
    printf("/n/n");
}
int getbyid_item(plist pl, int i)
{
    plist p=pl->next;
    int j=1;
    while(p && j<i)
    {
        p=p->next;
        j++;
    }
    if(!p || j>i)  /* >len or <1  */
    {
        printf("fail.../n");
        exit(1);
    }
    return p->data;
}
int locate_item(plist pl, int e)
{
    plist p=pl->next;
    int j=1;
    while(p->data != e && p->next)
    {
        p=p->next;
        j++;
    }
    if(p->data == e)
        return j;
    else
    {
        printf("There is n %d in list/n", e);
        return -1;
    }
}
void delete_item(plist pl, int i, int *e)
{
    plist p=pl;
    plist q;
    int j=1;
    while(p->next && j<i)
    {
        p=p->next;
        j++;
    }
    if(!p->next || j>i)  /* >len or <1  */
    {
        printf("fail..../n");
        return;
    }
    q=p->next;
    p->next=q->next;
    *e=q->data;
    free(q);
}
int len_list(plist pl)
{
    int j=0;
    plist p=pl;
    while(pl && p->next)
    {
        j++;
        p=p->next;
    }
    return j;
}
plist traverse_list(plist pl)
{
    plist h, p, s;
    
    if(!pl || !pl->next)
        return pl;
    h=pl->next;
    s=h;
    p=s->next;
    h->next=NULL;
    while(p)
    {
        s=p;
        p=p->next;
        s->next=h;
        h=s;
    }
    pl->next=h;
    
    return pl;
}
void main()
{
    int len, pos, *del;
    plist pl=NULL;
    del=(int *)malloc(sizeof(int));
    pl=init_list();
    isempty_list(pl);
    insert_item(pl, 1, 1);
    insert_item(pl, 2, 3);
    insert_item(pl, 3, 5);
    insert_item(pl, 4, 7);
    insert_item(pl, 5, 9);
    insert_item(pl, 6, 11);
    display(pl);
    len=len_list(pl);
    printf("link list len: %d/n", len);
    pos=locate_item(pl, 7);
    printf("num 7 pos: %d/n", pos);
    delete_item(pl, 3, del);
    printf("delete pos 3 num: %d/n", *del);
    display(pl);
    printf("link list traverse.../n");
    pl=traverse_list(pl);
    display(pl);
    destroy_list(pl);
    getch();
}

#include <stdio.h>
#include <malloc.h>
struct _node
{
    int data;
    struct _node *next;
};
typedef struct _node node, *plist;
plist init_list()
{
    plist pl=(plist)malloc(sizeof(node));
    if(!pl)
    {
        printf("error malloc fail.../n");
        return NULL;
    }
    pl->data=-1;
    pl->next=pl;    /* pl->next=NULL */
    return pl;
}
void insert_item(plist pl, int pos, int data)
{
    int j=0;
    plist p,s;
    s=p=pl;
    while(p && j<pos-1)
    {
        p=p->next;
        j++;
    }
    if(!p || j>pos-1)
    {
        printf("Error insert fail.../n");
        return;
    }
    s=(plist)malloc(sizeof(node));
    if(!s)
    {
        printf("Error malloc fail.../n");
        return;
    }
    s->data=data;
    s->next=p->next;
    p->next=s;
}
int find_item(plist pl, int data)
{
    plist s,p;
    s=p=pl;
    p=p->next;
    while(s != p)
    {
        if(data==p->data)
            return 1;
        p=p->next;
    }
    return 0;
}
void delete_item(plist pl, int data)
{
    plist p,s;
    s=p=pl;
    if(data == p->data) /* first item is equal with data, then last item = second item */
    {
        s=p;
        while(s != p->next)
            p=p->next;
        p->next=s->next;
        return;
    }
    while(s != p->next) /* first item is not equal with data */
    {
        if(data == p->next->data)
        {
            p->next=p->next->next;
            return;
        }
        p=p->next;
    }
}
void display(plist pl)
{
    plist s,p;
    s=p=pl;
    printf("%5d", p->data); /* print first item */
    p=p->next;
    while(s != p)
    {
        printf("%5d", p->data);
        p=p->next;
    }
    printf("/n/n");
}
void main()
{
    int f;
    plist pl;
    pl=init_list();
    insert_item(pl, 1, 1);
    insert_item(pl, 2, 3);
    insert_item(pl, 3, 5);
    insert_item(pl, 4, 7);
    insert_item(pl, 5, 9);
    display(pl);
    printf("Finding 3.../n");
    f=find_item(pl, 3);
    if(f)
        printf("True find 3/n");
    else
        printf("False find 3.../n");
    printf("/nDeleting 1.../n");
    delete_item(pl->next, 1);
    display(pl->next);
    getch();
}

#include <stdio.h>
#include <malloc.h>
struct _node
{
    int data;
    struct _node *prior;
    struct _node *next;
};
typedef struct _node node, *plist;
plist init_list()
{
    plist p;
    p=(plist)malloc(sizeof(node));
    if(!p)
    {
        printf("Error, malloc fail.../n");
        return NULL;
    }
    p->data=-1;   /* head->data = -1 */
    p->prior=p;
    p->next=p;
    return p;
}
void insert_item(plist pl, int pos, int data)
{
    int j=0;
    plist s,p;
    p=pl;
    while(p && j<pos-1)
    {
        p=p->next;
        j++;
    }
    if(!p || j>pos-1) /* pos is less than 1 or pos larger than len_list+1 */
    {
        printf("Error %d is invalide num.../n", pos);
        return;
    }
    s=(plist)malloc(sizeof(node));
    if(!s)
    {
        printf("Error, malloc fail.../n");
        return NULL;
    }
    s->data=data;
    s->prior=p;
    s->next=p->next;
    p->next->prior=s;
    p->next=s;
}
int find_item(plist pl, int data)
{
    plist s,p;
    s=p=pl;
    if(data == p->data)
        return 1;
    p=p->next;
    while(s != p)
    {
        if(data == p->data)
            return 1;
        p=p->next;
    }
    return 0;
}
void delete_item(plist pl, int data)
{
    plist s,p;
    s=p=pl;
    if(data == p->data) /* first check equal */
    {
        p->prior->next=p->next;
        p->next=p->prior;
        return;
    }
    while(s != p->next)
    {
        if(data == p->next->data)
        {
            p->next=p->next->next;
            p->next->next->prior=p;
        }
        p=p->next;
    }
}
void display(plist pl)
{
    plist s,p;
    s=p=pl;
    printf("%5d", p->data);  /* first item, such as head->data is -1 */
    p=p->next;
    while(s != p)
    {
        printf("%5d", p->data);
        p=p->next;
    }
    printf("/n/n");
}
void main()
{
    int f;
    plist pl;
    pl=init_list();
    insert_item(pl, 1, 1);
    insert_item(pl, 2, 3);
    insert_item(pl, 3, 5);
    insert_item(pl, 4, 7);
    insert_item(pl, 5, 9);
    display(pl);
    printf("Finding 3.../n");
    f=find_item(pl->next->next, 3);
    if(f)
        printf("True find 3/n");
    else
        printf("Fail find 3.../n");
    printf("Finding 6.../n");
    f=find_item(pl->prior->prior, 6);
    if(f)
        printf("True find 6/n");
    else
        printf("Fail find 6.../n");
    printf("/nDeleting 3.../n");
    delete_item(pl->next->next, 3);
    display(pl);
    getch();
}