C#创建随机唯一整数列表 [英] C# creating a list of random unique integers

问题描述

我需要创建一个包含十亿个整数的列表，并且它们都必须是唯一的.我还需要非常快地完成此操作.

I need to create a list with one billion integers and they must all be unique. I also need this to be done extremely fast.

创建列表并一个接一个地添加随机数，然后检查每个副本是否重复非常慢.

Creating a list and adding random numbers one by one and checking to see if each one is a duplicate is extremely slow.

如果我只是用随机数填充列表而不检查它们是否重复，然后使用distinct().toList()，这似乎会很快.我重复此操作，直到没有更多重复为止.但是，创建新列表使用的额外内存不是最佳的.有没有一种方法可以提高distinct()的性能，但是只创建源列表，而不是创建新列表，就可以了?

It seems to be quite fast if I just populate a list with random numbers without checking if they are duplicates and then using distinct().toList(). I repeat this until there are no more duplicates. However the extra memory used by creating a new list is not optimal. Is there a way to get the performance of distinct() but instead of creating a new list it just modifies the source list?

推荐答案

整数是否需要在一定范围内?如果是这样，则可以创建一个数组或列表，其中所有数字都在该范围内(例如，从1到1000000000)，然后对列表进行随机排列.

Do the integers need to be in a certain range? If so, you could create an array or list with all numbers in that range (for example from 1 to 1000000000) and shuffle that list.

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