C语言零移位操作

给定一个整形数组要求把其中的零元素移动到数组的末尾 非零元顺序保持不变

以下采用两种方法实现

 

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <windows.h>



void PrintArr( int arr[], int iSize )

{

	if( iSize < 0 )

		return;

	

	int i = 0;

	for( ; i < iSize; i++ )

	{

		if( !arr[i] )

			printf( "%d ", arr[i] );

	}



	puts( "" );

}



void LocalMove( int arr[], int iSize )

{//本地移动 速度极慢 优点是消耗内存空间少

	if( iSize <= 1 )

		return;



	int i,j;



	int iZeroCount = 0;//零元总数



	for( i = 0; i < iSize; i++ )

	{

		if( !arr[i] )

			iZeroCount++;

	}



	int iZeroCur = iZeroCount;

	

	for( i  = 0; i < iSize && iZeroCur > 0; i++ )

	{

		if( !arr[i] )

		{

			for( j = i; j < iSize - ( iZeroCount - iZeroCur ); j++ )

			{

				arr[j] = arr[j+1];

			}



			arr[j-1] = 0;

			iZeroCur--;

			i--;

		}

	}



	//PrintArr( arr, iSize );

}



int* CreateIntArr( int iSize )

{//创建整形数组

	puts( "CreateArr" );



	int* pIntArr = (int*)malloc( sizeof( int ) * iSize );



	if( !pIntArr )

		return NULL;



	srand( iSize );



	int i = 0;

	for( ; i < iSize; i++ )

	{

		if( 0 == i % 2 )

			*( pIntArr + i ) = rand();

		else

			*( pIntArr + i ) = 0;

	}



	puts( "Finish create array!" );



	return pIntArr;	

}



int* CopyArr( int* pArrInt, int iSize )

{//复制整形数组

	if( !pArrInt || iSize <= 0 )

		return  NULL;



	int* pNewArr = (int*)malloc( sizeof( int ) * iSize );



	if( !pNewArr )

		return NULL;



	puts( "Starting copy array ..." );

	int i = 0;

	for( ; i < iSize; i++ )

	{

		*( pNewArr + i ) = *( pArrInt + i );

	}



	puts( "Finish copy array..." );



	return pNewArr;

}

void SaveMove( int arr[], int iSize )

{//空间换时间 这个算法的速度是上个算法速度的8万倍以上 这个专卖值得做

	if( iSize <= 1 )

		return;



	int i  = 0;

	int iNoneZero = 0;



	for( ; i < iSize; i++ )

	{

		if( arr[i] )

			iNoneZero++;

	}



	int* pIntArr = (int*)malloc( sizeof( int ) * iNoneZero );

	int iCur = 0;

	for( i = 0; i < iSize && iNoneZero > 0; i++ )

	{

		if( arr[i] )

		{

			*(pIntArr + iCur++) = arr[i];

			iNoneZero--;

		}

	}

	

	memset( arr, 0, iSize );

	for( i = 0; i < iCur; i++ )

	{

		arr[i] = *( pIntArr + i );

	}



	//PrintArr( arr, iSize );

}







int main( int argc, char* argv[] )

{

	if( argc < 2 )

	{

		puts( "Usage: MoveZero.exe number" );

		return -1;

	}



	int iNum = atoi( argv[1] );



	if( iNum <= 0 )

	{

		puts( "Error argument!" );

	}



	int* pIntArrOne = CreateIntArr( iNum );

	int* pIntArrTwo = CopyArr( pIntArrOne, iNum );



	long lStart;

	

	lStart = GetTickCount();

	puts( "LocalMove" );

	LocalMove( pIntArrOne, iNum );

	printf( "LocalMove Cost Time: %ld\n", GetTickCount() - lStart );



	lStart = GetTickCount();

	puts( "SaveMove" );

	SaveMove( pIntArrTwo, iNum );

	printf( "SaveMove Cost Time: %ld\n", GetTickCount() - lStart );



	return 0;

}

 

测试结果如下：

C:\Users\fzql>"F:\MyDocument\Visual Studio 2008\Projects\VCInterview\VCInterview
\Debug\VCInterview.exe" 102400
CreateArr
Finish create array!
Starting copy array ...
Finish copy array...
LocalMove
LocalMove Cost Time: 16208
SaveMove
SaveMove Cost Time: 0

C:\Users\fzql>"F:\MyDocument\Visual Studio 2008\Projects\VCInterview\VCInterview
\Debug\VCInterview.exe" 1024000
CreateArr
Finish create array!
Starting copy array ...
Finish copy array...
LocalMove
LocalMove Cost Time: 1377832
SaveMove
SaveMove Cost Time: 16