代码

unsigned cnt[4][257];
void sort(unsigned *a,int n)
{
unsigned *b=new unsigned[n]();
	int base=8,mask=(1U<<base)-1;
	for(int ba=0,x=0;ba<32;ba+=base,x++)
	{
		unsigned *cc=cnt[x];
		for(int i=0;i<n;++i) ++cc[a[i]>>ba&mask];
		for(int i=1;i<=mask;++i) cc[i]+=cc[i-1];
		for(int i=n-1;~i;--i) b[--cc[a[i]>>ba&mask]]=a[i];
		for(int i=0;i<n;++i) a[i]=b[i];
	}
delete[] b;
}

评测结果