C++ - Finding intersection of two ranges

c++ range intersection set-intersection
1110101001 picture 1110101001 · Nov 16, 2013 · Viewed 9.3k times · Source

What is the best way to find the intersection of two ranges in C++? For example, if I have one range as [1...20] inclusive, and another as [13...45] inclusive, I want to get [13...20], as that is the intersection between them.

I thought about using the native set intersection function in C++, but I would first have to convert the range into a set, which would take too much computation time for large values.

Answer

Angew is no longer proud of SO picture Angew is no longer proud of SO · Nov 16, 2013 
intersection = { std::max(arg1.min, arg2.min), std::min(arg1.max, arg2.max) };
if (intersection.max < intersection.min) {
  intersection.markAsEmpty();
}

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