RLE压缩和解压算法以及链表翻转

 

#include
#include

struct RleNode
{
    int count;
    char ch;
    struct RleNode * next;
};

//压缩字符串
struct RleNode* encode(char *str)
{
    char *ptr = str;
    int num = 1;
    int i = 0;
    struct RleNode* head, *p, *q;

    head = (struct RleNode*)malloc(sizeof(struct RleNode));
    head->next = NULL;
    p = head;

    while(*ptr != '\0')
    {
        char ch  = *ptr;
        char ch2  = ptr[i];
        char ch3  = ptr[i + 1];

        if(ptr[i] == ptr[i + 1])
        {
            num++;
        }

        if((ptr[i] != ptr[i + 1]) )
        {
            q = (struct RleNode*)malloc(sizeof(struct RleNode));
            q->count = num;
            q->ch = ptr[i];
            q->next = NULL;

            p->next = q;
            p = q;
            num = 1;
        }
        ptr++;
    }
    return head;
}

//解压字符串
char *decode(struct RleNode* head)
{
    char *str = calloc(1,100);
    int num = 0;
    int i = 0;
    struct RleNode* p= head->next;
    if(p == NULL)
    {
        printf("空表");
    }
    else
    {
        while(p->next != NULL)
        {
            num = p->count;
            while(num > 0)
            {
                str[i] = p->ch;
                i++;
                num--;

            }
            p = p->next;

        }
        num = p->count;
        while(num > 0)
        {
            str[i++] = p->ch;
            num--;

        }
    }
    return str;
}

//链表反转
struct RleNode* reverse(struct RleNode* head)
{
    struct RleNode *prev = NULL, *current = NULL, *p = head->next;
    if(p == NULL)
    {
        printf("空表");
    }
    while(p != NULL)
    {
        prev = current;
        current = p;
        p = p->next;
        current->next = prev;
    }
    head->next = current;
    return head;
}

//显示链表
void disp(struct RleNode* head)
{
    struct RleNode* p= head->next;

    if(p == NULL)
    {
        printf("空链表");

    }
    else
    {
        while(p->next != NULL)
        {
            printf("%d%c", p->count, p->ch);
            p = p->next;
        }
        printf("%d%c\n", p->count, p->ch);
    }

}
int main()
{
    struct RleNode* head = (struct RleNode*)malloc(sizeof(struct RleNode));
    char *str = "aaaaahhhhhhmmmmmmmuiiiiiiiaaaaaa";
    printf("源字符串：%s\n",str);
    head = encode(str);
    printf("压缩后为：");
    disp(head);
    head = reverse(head);
    printf("反转后：");
    disp(head);
    printf("解压后为：%s",decode(head));
    return 0;
}