跳表代码

跳表根据逐层元素减半的方式，能够对有序链表进行快速的插入，查找，删除等操作。

skip_list.h声明

#define MAX_LEVEL 8

typedef struct Node_s
{
	int value;
	struct Node_s *next[1];
}Node;

typedef struct SkipList_s
{
	int level;
	Node *head;
}SkipList;

Node *CreateNode(int level, int value);
SkipList *Init();
int Random();
void Insert(SkipList *list, int value);
void Delete(SkipList *list, int value);
void Show(SkipList *list);

skip_list.c内部实现

#include 
#include 

#include "slip_list.h"

Node *CreateNode(int level, int value)
{
	Node *node = (Node *)malloc(sizeof(Node) + (level - 1) * sizeof(Node *));
	node->value = value;
	return node;
}

SkipList *Init()
{
	int i;
	SkipList *list = (SkipList *)malloc(sizeof(SkipList));
	list->level = 0;
	list->head = CreateNode(MAX_LEVEL, 0);
	for (i = 0; i < MAX_LEVEL; i++) {
		list->head->next[i] = NULL;
	}
	return list;
}

int Random()
{
	int k = 1;
	while (rand() % 2) {
		k++;
	}
	return k > MAX_LEVEL ? MAX_LEVEL : k;
}

void Insert(SkipList *list, int value)
{
	int i, k;
	Node *update[MAX_LEVEL];
	Node *node;
	Node *p, *q = NULL;
	p = list->head;
	k = list->level;

	for (i = k - 1; i >= 0; i--) {
		while ((q = p->next[i]) && (q->value <= value)) {
			if (q->value == value) {
				printf("error:insert error %d\n", value);
				return;
			}
			p = q;
		}
		update[i] = p;
	}

	k = Random();
	if (k > list->level) {
		for (i = list->level; i < k; i++) {
			update[i] = list->head;
		}
		list->level = k;
	}

	node = CreateNode(k, value);
	printf("k: %d    level: %d\n", k, list->level);
	for (i = 0; i < k; ++i) {
		node->next[i] = update[i]->next[i];
		update[i]->next[i] = node;
	}
}

void Delete(SkipList *list, int value)
{
	int i, k;
	Node *update[MAX_LEVEL];
	Node *p, *q = NULL;
	p = list->head;
	k = list->level;

	for (i = k - 1; i >= 0; i--) {
		while ((q = p->next[i]) && q->value < value) {
			p = q;
		}
		update[i] = p;
	}
	
	if (q && (q->value == value)) {
		for (i = 0; i < k; i++) {
			if (update[i]->next[i] == q) {
				update[i]->next[i] = q->next[i];
			}
		}
		free(q);

		for (i = list->level - 1; i >= 0; i--) {
			if (list->head->next[i] == NULL) {
				list->level--;
			}
		}
	}
}

void Show(SkipList *list)
{
	int i;
	Node *p, *q = NULL;
	for (i = list->level - 1; i >= 0; i--) {
		printf("\n======== levle %d ========\n", i);
		p = list->head;
		while (q = p->next[i]) {
			printf("%d -> ", q->value);
			p = q;
		}
		printf("\n");
	}
	printf("\n");
}

主函数测试代码：

#include 
#include 
#include 
#include "slip_list.h"

typedef unsigned int uint32;

uint32 get_time()
{
    uint32 current_time = 0;
    current_time = GetTickCount();
    return current_time;
}

int main()
{
	int i;
	int ar[] = {5, 7, 6, 4, 3, 9, 0, 1, 8, 2, 2};
	uint32 start_time, end_time;
	SkipList *list;

	list = Init();

	start_time = get_time();
	for (i = 0; i < 40000; i++) {
		Insert(list, rand());
	}
	end_time = get_time();

	printf("Time consumed %d\n", end_time - start_time);

	Show(list);
	Show(list);
	Delete(list, 8);
	Show(list);

	_asm int 3
}