代码

unsigned B[10005];
unsigned s[256],s1[256],s2[256],s3[256];
void radix_sort_(unsigned *A,int l,int r){  //a[i]>=0, -O2
	const unsigned base = 255;
	A+=l-1;r-=l-1;l=1;
	/*for (int i=0;i<=base;++i)s[i]=0;
	for (int i=0;i<=base;++i)s1[i]=0;
	for (int i=0;i<=base;++i)s2[i]=0;
	for (int i=0;i<=base;++i)s3[i]=0;*/
	unsigned x;
	for (int i=1;i<=r;++i){
		x=a[i];
		++s[x&base];
		++s1[x>>8&base];
		++s2[x>>16&base];
		++s3[x>>24];
	}
	for (int i=1;i<=base;++i){
		s[i]+=s[i-1];
		s1[i]+=s1[i-1];
		s2[i]+=s2[i-1];
		s3[i]+=s3[i-1];
	}
	for (int i=r;i>=1;--i)b[s[a[i]&base]--]=a[i];
	for (int i=r;i>=1;--i)a[s1[a[i]>>8&base]--]=b[i];
	for (int i=r;i>=1;--i)b[s2[a[i]>>16&base]--]=a[i];
	for (int i=r;i>=1;--i)a[s3[a[i]>>24]--]=b[i];
	//if (a!=A)for (int i=1;i<=r;++i)A[i]=a[i];
}

void sort(unsigned *a, int n){
	radix_sort_(a, 0, n-1);
}

评测结果