Recently, I was looking at [this Kattis problem](https://open.kattis.com/problems/starwarsmovies). I was considering a (perhaps simpler, i.e. smaller bounds on Q) online version of the problem, and considered using it as an opportunity to learn the GNU policy-based ordered set data structure (for C++). I first noticed that the structure of the define statement could be modified to support different data types other than just ints.↵
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For example, this:↵
`#define ordered_set tree<pair<int, int>, null_type,less<pair<int, int>>, rb_tree_tag,tree_order_statistics_node_update>`↵
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instead of this: `#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>`↵
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Obviously, the two main functionalities of this data structure are `find_by_order(x)` and `order_of_key(x)`. However, when using the ordered set with pair<int, int> as the data type, I noticed that when trying to use the `find_by_order(x)` method (by passing in an int as a parameter), my code was immediately throwing a long, practically unreadable error.↵
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I was wondering if anyone familiar with C++ or GNU PDBBDS could help explain what is going on (I can send my code so far if necessary). Any help would be appreciated.↵
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Thank you.
↵
For example, this:↵
`#define ordered_set tree<pair<int, int>, null_type,less<pair<int, int>>, rb_tree_tag,tree_order_statistics_node_update>`↵
↵
instead of this: `#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>`↵
↵
Obviously, the two main functionalities of this data structure are `find_by_order(x)` and `order_of_key(x)`. However, when using the ordered set with pair<int, int> as the data type, I noticed that when trying to use the `find_by_order(x)` method (by passing in an int as a parameter), my code was immediately throwing a long, practically unreadable error.↵
↵
I was wondering if anyone familiar with C++ or GNU P
↵
Thank you.
