第11章 散列表

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

unsigned int hashIndex1(const char *key, unsigned int tablesize)
{
	unsigned int val = 0;
	while (*key != '\0')
		val += *key++;
	return val%tablesize;
}
unsigned int hashIndex2(const char *key, unsigned int tablesize)
{
	return (key[0] + 27 * key[1] + 729 * key[2]) % tablesize;
}
unsigned int hashIndex3(const char *key, unsigned int tablesize)
{
	unsigned int val = 0;
	while (*key != '\0')
		val = (val << 5) + *key++;
	return val%tablesize;
}
unsigned int hashIndex4(unsigned int key, unsigned int tablesize)
{
	return key%tablesize;
}
struct ListNode{
	int value;
	ListNode* next;
};
struct HashTab{
	int tablesize;
	ListNode** list;
};
HashTab initializeTable(int tablesize)
{
	HashTab h;
	h.tablesize = tablesize;
	h.list = (ListNode**)malloc(sizeof(ListNode*)*tablesize);
	for (int i = 0; i < tablesize; ++i)
		h.list[i] = NULL;
	return h;
}
ListNode* FindHash(HashTab h, int key)
{
	ListNode* L = h.list[ hashIndex4(key, h.tablesize) ];
	while (L&&L->value != key) L = L->next;
	return L;
}
void InsertHash(HashTab h, int key)
{
	ListNode* p = FindHash(h, key);
	if (p == NULL){
		ListNode* newcell = (ListNode*)malloc(sizeof(ListNode));
		newcell->next = NULL;
		newcell->value = key;
		//printf("%d\n", hashIndex4(key, h.tablesize));
		int index = hashIndex4(key, h.tablesize);
		if (h.list[index] == NULL) h.list[index] = newcell;
		else{
			newcell->next = h.list[index];
			h.list[index] = newcell;
		}
	}
}

void printHash(HashTab h)
{
	ListNode* tmp;
	for (int i = 0; i < h.tablesize; ++i){
		tmp = h.list[i];
		while (tmp){
			printf("%d\t", tmp->value);
			tmp = tmp->next;
		}
		printf("\n");
	}
}
int main()
{
	int a[] = { 4, 2, 2, 0, 20, 11, 15, 18, 20, 13 };
	HashTab h = initializeTable(5);
	for (int i = 0; i < 10; ++i)
		InsertHash(h, a[i]);
	printHash(h);
}