线性排序之计数排序

/**
* @brief counting sort
* @author An
* @data  2013.5.18
**/

int* CountingSort( int *array, int length, int range )
{
int *count = new int[range + 1];
int *res = new int[length];
for ( int i = 0; i <= range; ++i )
{
count[i] = 0;
}
for ( int i = 0; i < length; ++i )
{
count[ array[i] ]++;
}
for ( int i = 1; i <= range; ++i )
{
count[i] += count[i - 1];
}
for ( int i = length - 1; i >= 0; --i )
{
res[ count[ array[i] ] - 1 ] = array[i];// index is from 0!
--count[ array[i] ];
}
delete [] count;
return res;
}