[置顶] Hash查找,散列查找

//Hash.h

#ifndef HASH_H
#define HASH_H
#define HASH_ARR_SIZE 100
#define FILL -1

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

struct _Node
{
	int iFill;
	int iValue;
	struct _Node* pNext; 
};

typedef _Node Node;

typedef struct
{
	Node* pHashArr;
	int iArrSize;
	int iSize;
}Hash;

#endif

//Hash.c

#include "Hash.h"

Hash* CreateHashArr()
{
	Hash* pHash = (Hash*)malloc( sizeof( Hash ) );

	if( !pHash )
		return NULL;

	pHash->iArrSize = HASH_ARR_SIZE;
	pHash->iSize = 0;
	pHash->pHashArr = (Node*)malloc( sizeof( Node ) * HASH_ARR_SIZE );
	
	memset( pHash->pHashArr, 0, sizeof( Node ) * HASH_ARR_SIZE );

	if( !pHash->pHashArr )
		return NULL;

	return pHash;
}

int GetIndex( int iValue )
{
	return iValue % HASH_ARR_SIZE;
}

Node* CreateNode( int iValue )
{
	Node* pNode = (Node*)malloc( sizeof( Node ) );

	if( !pNode )
		return NULL;

	pNode->iValue = iValue;
	pNode->pNext = NULL;
	pNode->iFill = FILL;

	return pNode;
}

int DoHash( Hash* pHash, int iValue )
{
	if( !pHash )
		return -1;

	int iIndex = GetIndex( iValue );

	if( (pHash->pHashArr + iIndex)->iFill != FILL )
	{
		(pHash->pHashArr + iIndex)->iFill = FILL;
		(pHash->pHashArr + iIndex)->iValue = iValue;
		(pHash->pHashArr + iIndex)->pNext = NULL;

		pHash->iSize++;
	}
	else
	{//collison
		Node* pNode = (pHash->pHashArr + iIndex)->pNext;

		if( !pNode )
		{
			(pHash->pHashArr + iIndex)->pNext = CreateNode( iValue );

			return 0;
		}

		Node* pPrior = pNode;

		while( pNode )
		{
			pPrior = pNode;
			pNode = pNode->pNext;
		}

		pNode = CreateNode( iValue );

		if( !pNode )
			return -1;

		pPrior->pNext = pNode;
		pHash->iSize++;
	}	
	
	return 0;
}

Node* HashSearch( Hash* pHash, int iValue )
{
	if( 0 == pHash->iSize )
		return NULL;

	int iIndex = GetIndex( iValue );

	if( (pHash->pHashArr + iIndex)->iFill != FILL )
		return NULL;
	else
	{
		if( (pHash->pHashArr + iIndex)->iValue == iValue )
			return pHash->pHashArr + iIndex;

		Node* pNode = (pHash->pHashArr + iIndex)->pNext;
		Node* pPrior = pNode;

		while( pNode && pPrior->iValue != iValue )
		{
			pPrior = pNode;
			pNode = pNode->pNext;
		}

		if( pNode->iValue == iValue )
			return pNode;

	}
	
	return NULL; 
}

void PrintNode( Node* pNode )
{
	if( pNode )
		printf( "%d ", pNode->iValue );
}

int main( int argc, char* argv[] )
{
	Hash* pHash = CreateHashArr();

	if( !pHash )
		return -1;
	
	DoHash( pHash, 1 );
	DoHash( pHash, 300 );
	DoHash( pHash, 22 );
	DoHash( pHash, 11 );
	DoHash( pHash, 99 );
	DoHash( pHash, 28 );
	DoHash( pHash, 36 );
	DoHash( pHash, 23 );
	DoHash( pHash, 55 );
	DoHash( pHash, 3 );
	DoHash( pHash, 7 );
	DoHash( pHash, 101 );
	
	PrintNode( HashSearch( pHash, 1 ) );
	PrintNode( HashSearch( pHash, 101 ));

	return 0;
}