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Tag: set

Tranforming a Map containing Sets into a Map of Set-Sizes [closed]

Closed. This question needs debugging details. It is not currently accepting answers. Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question. Closed last month. Improve this question This is my hash map: How can I get a new HashMap that will

Java: join the values of a map containing sets

Consider the following pseudo Map<String, Set<String>>: What is the best way to join the value Sets into a single Set (above example should be [“A”, “B”, “C”, “D”]). The order of the resulting set does not matter. I know that I can to something like this: But it feels kind of ugly and I’m wondering if there is a better

TreeSet throws nullpointer exception when using custom comparator

I got an error msg when I trying to remove a specific element in treeset (not null). I’m not sure why this happened, and I tried to use contains to check if there has the same element in the set already which would work fine. The exception throws when calling reset method. Here is my code: Answer As @VGR mentioned:

Merge sets when two elements in common

This is the follow up of compare sets I have I want to merge the sets when there are two elements in common. For example 0,1,2 and 0,2,6 has two elements in common so merging them to form [0,1,2,6]. Again [0,1,2,6] and [2,6,7] has 2 and 6 common. so merging them and getting [0,1,2,6,7]. The final output should be :