代码

void sort(unsigned *a, int n){
    #define N 100000000
    #define D 256
    #define D1 255
    #define cal(w,w2,tw,op)\
    p=w2-1;\
    for(i=0;i<D;++i)rs[i]=p,p+=tw[i];\
    for(i=0;i<N;i+=8){\
    	p=w+i;\
    	*++rs[p[0]op]=p[0],\
    	*++rs[p[1]op]=p[1],\
    	*++rs[p[2]op]=p[2],\
    	*++rs[p[3]op]=p[3],\
    	*++rs[p[4]op]=p[4],\
    	*++rs[p[5]op]=p[5],\
    	*++rs[p[6]op]=p[6],\
    	*++rs[p[7]op]=p[7];\
    }
    unsigned b[N],*rs[D],t0[D],t1[D],t2[D],t3[D];
    register unsigned*p,i,x;
    for(i=0;i<D;++i){
    	t0[i]=0,
    	t1[i]=0,
    	t2[i]=0,
    	t3[i]=0;
    }
    for(i=0;i<N;){
    #define A x=a[i];++t0[x&D1];++t1[x>>8&D1];++t2[x>>16&D1];++t3[x>>24];++i;
    A A A A
    }
    cal(a,b,t0,&D1),
    cal(b,a,t1,>>8&D1),
    cal(a,b,t2,>>16&D1),
    cal(b,a,t3,>>24);
}

评测结果