[Leetcode]-ReverseLinkedList

题目：单链表取反

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

typedef struct node *list;
typedef struct node *position;
typedef struct node *ListNode;

typedef struct node
{
    int data;
    position next;
}node;

static list init_list(void);
static void delete_list(list L);
static int isempty(list L);
static void insert_node(position L,int data);
static void delete_node(list L,position P);
static position find_last(list L);
static position find_value(list L,int data);
static position find_pre(list L,position P );
static void print(list L);



list init_list(void){
    list L  = (list)malloc(sizeof(node));
    L->next = NULL;
    return L;
}
void delete_list(list L){
    position P ,next;
    P = L;
    do{
        next = P->next;
        free(P);
        P = next;
    }while(next != NULL);
}
int isempty(list L){
    return (L->next == NULL);
}
void insert_node(position P,int data){
    position tem ;
    tem = (position)malloc(sizeof(node));
    tem->data = data;
    tem->next = P->next;
    P->next = tem;
}
void delete_node(list L,position P){
    position pre ;
    pre = find_pre( L, P);
    if(pre != NULL)
    {
        pre->next = P->next;
        free(P);
    }
    else
    {
        printf("delete_node:p is not in the list!
");
    }

}
position find_last(list L){
    position P;
    P=L;
    while(P->next != NULL)
    {
        P = P->next;
    }
    return P;

}
position find_value(list L,int data){
    position P ;
    P = L;
    while(P->next != NULL)
    {
        P = P->next;
        if(P->data == data)
            return P;
    }
    return NULL;
}

position find_pre(list L,position P ){
    position tem ;
    tem = L;
    while(tem->next != NULL)
    {
        if(tem->next == P)
            return tem;
        tem = tem->next;
    }
    return NULL;
}
void print(list L){
    position P;

    if(isempty( L))
    {
        printf("print: L is a null list!
");
        return ;
    }
    P = L;
    while(P->next !=NULL)
    {
        P = P->next;
        printf("print:%p : %d 
",P,P->data);
    }
    printf("
");
}

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     struct ListNode *next;
 * };
 */
ListNode reverseList( ListNode head) {

    if((head == NULL)||(head->next == NULL) )
        return head;
    ListNode  cur= head;
    ListNode  tempt=NULL;

    while (cur->next!=NULL&& cur!=NULL)
    {
        tempt=cur->next;
        cur->next=tempt->next;
        tempt->next=head;
        head=tempt;
        tempt=cur->next;
    }

    return head;
}

int main()
{
    int a[6]= {1,2,3,4,5,6};
    int i=0;
    list L,L1;
    L = init_list();

    print(L);
    printf("insert node
");
    for(i=0;i<6;i++)
    {
        insert_node( L,a[i]);
    }
    print( L);
    L1 = reverseList(L);
    print( L1);
}