代码

int binary_search(register const unsigned *a, register const int n, register unsigned x)	{
	register int l = 0, r = n - 1, mid;
	while(l < r)	{
	    mid = (l + r) >> 1;
	    if(a[mid] < x)	l = mid + 1;
	    else 		r = mid;
	}
	return l;
}

评测结果