代码

void sort(unsigned *a, int n) {
    const int maxn = 1 << 27;
    static unsigned A[maxn];
    for (int i = 0; i < n; i+=4)
    {
        A[a[i] >> 5] |= 1u << (a[i] & 31ull);
        A[a[i+1] >> 5] |= 1u << (a[i+1] & 31ull);
        A[a[i+2] >> 5] |= 1u << (a[i+2] & 31ull);
        A[a[i+3] >> 5] |= 1u << (a[i+3] & 31ull);
    }
    
    for(unsigned i = 0; i < maxn; ++i)
    {
    	while(A[i])
    	{
    		int t = __builtin_ctz(A[i]);
    		*(a++) = (i << 5) + t;
    		A[i] ^= (1u << t);
	}
    }
}

评测结果