Mytl3

A C++ competitive programming library.

Features

• 10-second setup! (all functions in one file)
• Doesn't let you to use int, to prevent Integer Overflow Errors (unless you really want to, then use need_int). Use ll (short for long long) instead.
• Shortcuts for commonly used functionality (eg. Mod107 for a Modulo 10^9+7 type, vector_memo for memoization using vectors, etc...)
• Some convenience functions to simplify often occurring patterns such as memoizing a recursive function or making calculations modulo 10^9+7.
• Segment tree, Modulo Integer Class, Trie, Memoization using any underlying Data Structure
• Sample usage code snippet below every functionality
• Generality of Data Structures achieved using C++ templates
• Debug assertions in the code to minimise the chance of incorrect usage

Another CP library?

Many CP libraries exist, but most have algorithms implemented for one specific type (eg. Segment Tree can only calculate sum of int-s), so they often can't be used without modifying the code.

Type-agnostic implementations eliminate the need to modify implementations for each use case by supplying use-case-specific logic via C++ templates (eg. underlying Data Structure for Memoization, or the "sum" operation for Segment Tree)

In addition, this library has a focus on safety. For example, int-s are rarely a good idea to use in online CP contests, hence the macro preventing the appearance of int in the code (if you absolutely need int-s, use need_int which is a synonym).

Examples

Modulo 10^9+7:

mytl::Mod107 x = 43; //The value of x will always be calculated modulo 10^9+7. Mod107 is a synonym for TSModulo<100000007>
x = x / 2; //Mod107 works with all four elementary numeric operations
cout<<x.get(); //x.get() returns the numeric value of x

Segment Tree (updating operation: addition, querying operation: sum):

mytl::Node<mytl::Add_Sum<long long> > tree({1,1e+10}); //Create a segment tree with 10^10 elements. As the name Add_Sum suggests, you can add a value to any range and query the sum of any range in O(log n) time.
tree.query({1, 10}, 2); //Add 2 to every element with index in the range {1, ... 10}.
cout<<tree.query({5,14}, 0); //Print the sum of elements with index in range {5, ... 14}.

Unnecessary use of int:

int value_that_could_be_very_big; // compile error: macros prevent you from writing int in your code to prevent Integer Overflow
need_int not_big_value = 0; //OK! you can use 'need_int' if you really need int's

Further examples are in the codeforces_tests folder: these are correct solutions of Codeforces problems, that use the library.

Install

Copy templates/basic.cpp into your editor and you can start making your solution right away (by modifying the main function).

Contribute

• Very easy: if you use the library to solve a Codeforces problem, your solution becomes a test after you copy it under the path codeforces_tests/{any_name}.{contest_number}.{problem_letter}.cpp.
• To add/change the functionality itself, fork and make a pull request.