如何制作HashSet <HashSet<int> &gt;工作正常吗？

Question

I have a program where I use an algorithm to determine the 'indices' of an object to determine if it's a unique object, or if it is really holding the same data as another similar object.

The problem is that because of the way this object was created, I can't rely on these indices being in the same order.

For example, an object with indices:

[0, 1, 2] is the same as the object as [0, 2, 1] .

To handle this problem, I've been putting these indices into a HashSet<int> , in the hopes that when I go to compare the sets in the future, it will be easy because in set notation, {0, 1, 2} is the same as {0, 2, 1} .

The thing is, I can't just go

Object1.UniqueHashSet.equals(Object2.UniqueHashSet) 

because I have A LOT of these objects to compare, and I need to determine how many unique objects I have in a list of these.

To get around this, I've been trying to add these structures into a HashSet<HashSet<int>> of themselves, so that in the end I can just return the number of elements in the HashSet.

When I go to add the HashSet<int> into the HashSet<HashSet<int>> with values {0, 1, 2} , and then later add the HashSet<int> of {0, 2, 1} into the HashSet<HashSet<int>> it creates two new elements in the set, when I really only wanted one. So it turns out I have: {{0, 2, 1}, {0, 1, 2}} , when I really wanted {{0, 2, 1}} .

I've been racking my brain against the wall for hours trying to figure out how to do this. Can someone please point me in the right direction?

Answer 1

You'll want to create an inherited class of HashSet. You'll want to override the following methods:

public override int GetHashCode() { /* Implementation */ }
public override bool Equals(object obj) { /* Implementation */ }

The properties will be based on the members of the set.

Then, inserting into the HashSet of the custom class will not lead to duplicates.

You'll have a structure like:

HashSet<MyHashSet<int>>

The GetHashCode should be a computation based on the individual values in the set. The Equals should be checking for equals for the members of the set.

Here's some more information on the topic:

How should I override Equals and GetHashCode for HashSet?