QSet in QMap or QHash
c++, comparison, qmap, qt, qt4
Solution
You seem to know how to make it work: define an `operator<(const QSet<int>&)` function (I don't believe Qt requires that you subclass QSet to make this work, I know STL does not).
Obviously, implementing a comparator on an unordered set is going to be difficult. And doing it such that it runs in constant time is, I believe, impossible. You might try something like checking the size first, and then sorting and comparing the two contents as lists.
But broadly: don't do this. It's an abuse. Surely there is something you can use for the key of your set that is not a mutable data structure. Is the space of integers in the sets fixed and small (i.e. always in the range 0-1024 or whatnot)? Then try a bitmask stored in a QByteArray. etc...
Problem
I have `QMap` and I want to make `QSet` the key of it, I couldn't do that because `QSet` is not comparable. for example: ``` QSet<int> intSet; QMap<QSet<int>, char> charSet; intSet.insert(1); intSet.insert(2); intSet.insert(3); charSet.insert(intSet, '6'); ``` Is there any way to make it work? and if I inherit from `QSet` and define `operator <` how should I implement it? i.e: What should be the logic of the comparison? Note: I care too much about performance