c – 如何检查一个矢量是否是另一个矢量的子集？

目前,我认为我最好的选择是使用std :: set_intersection,然后检查较小输入的大小是否与set_intersection填充的元素数量相同.

有更好的解决方案吗？

解决方法

尝试这个：

if (std::includes(set_one.begin(),set_one.end(),set_two.begin(),set_two.end()))
{
// ...
}

约includes().

The includes() algorithm compares two
sorted sequences and returns true if
every element in the range [start2,
finish2) is contained in the range
[start1,finish1). It returns false
otherwise. includes() assumes that the
sequences are sorted using
operator<(),or using the predicate
comp.

跑进来

At most ((finish1 – start1) + (finish2
– start2)) * 2 – 1 comparisons are performed.

Plus O(nlog(n))用于排序向量.你不会比它快得多.