Yep, these Leetcode solutions *run in constant time!
*but they don't necessarily compile in constant time.
This repository is collection of solutions to common Leetcode problems, but all of them have been rewritten as templated metaprograms in C++. Templates in C++ are Turing complete and allow the execution of any algorithm at compile-time.
The metal library is used to provide convenient containers like lists, maps, and libraries, as well as operations on those containers and integral types.
constexpr-based solutions are not included. This would defeat the
purpose of using only templates to achieve compile-time solutions; people could
just copy-paste their existing C++ solutions into a constexpr function.
Run the following commands to execute an out-of-source build:
mkdir build
cd build
cmake ..
make -j{NPROC}
It is recommended to set {NPROC} to a value greater than 1 because it allows multiple solutions to be built at once. The test cases included in the solutions have been designed to not take an obscene amount of time compilation-wise - remember that with larger test cases, the more time the compiler will take to calculate solutions, depending on the time complexity of the algorithm.
Testing can either be done at compile-time or at run-time or both. metal gives the
IS_SAME macro as a way of producing compile-time checks to make sure that
types match. However, metaleet uses the Catch2 framework
to test the value of returned types (specifically integral types) at run-time.
As such, every solution contains a test case:
TEST_CASE("Test cases for problem #...") {
REQUIRE(solve<...>() == ...);
}