Vim Snippets for Competitive Programming

Write your snippets for competitive programming (CodeJam, Codeforces, HackerCup, TopCoder, etc.) with all the flexibility of UltiSnips. Ensure they works correctly by writing your own unit tests using gtest.

Installation

It is recommended to use Vundle to install this plugin (it's cleaner this way). You will also need UltiSnips to use these snippets. In your .vimrc:

Plugin 'SirVer/ultisnips'         "required
Plugin 'hav4ik/contest-snippets'  "that's all :)

Additionally, you might want to install vim-snippets for other useful snippets. I personally don't use it.

Implemented algorithms

• Number Theory
  • GCD
  • GCD extended
  • Prive Sieve in 4 variations:
    • Returns a bool vector
    • Returns a factorization vector
    • Returns a vector of primes
    • Memory-optimized for large upper bound
  • Chinese theorem solver

Writing and testing your own snippets

You can write your own snippets using c or c++, test them and convert them into UltiSnips-compatible snippets. To do that, you'll need to:

1. Install Google Test and Google Mock: If you are using ubuntu, the easiest way is:

   $ sudo apt-get install libgtest-dev
   $ cd /usr/src/gtest
   $ sudo cmake CMakeList.txt
   $ sudo make
   $ sudo cp *.a /usr/local/lib
   # sudo apt install google-mock
   

   Or, you may follow instructions from official repository to build and install Google Test.

2. Write your own snippets:

   Create your code file src/snippets/my.cpp. A minimal snippet might look as follows:

   // this header contains neccessary macros
   #include "common.hpp"
   
   // google test framework
   #include <gtest/gtest.h>
   
   // don't do that in serious projects, it's shit
   using namespace std;
   
   //     trigger   snips file   title        detailed description
   SNIPPET("pow", "my.snippets", "a^n", "calculates power in O(log n)")
   TABSTOP(1,int) fastpow(MIRROR(1,int) a, MIRROR(1,int) n) {
       MIRROR(1,int) res = 1;
       while(n)
           if (n & 1) { res *= a; --n; }
           else {a *= a; n >>= 1; }
       return res;
   }
   TABSTOP(0)
   TESTSNIPPET
   TEST(FastPower, CommonCases) {
       ASSERT_EQ(fastpow(2, 8), 256);
       ASSERT_EQ(fastpow(3, 7), 2187);
   }
   TEST(FastPower, EdgeCases) {
       ASSERT_EQ(fastpow(0, 0), 1);
   }
   ENDSNIPPET
   

   Compile, test and generate an UltiSnips-like snippet as follows:

   $ cmake CMakeLists.txt
   $ make
   

   Now, there should be a file my.snippets in the folder UltiSnips/cpp/, which will look as follows:

   snippet pow "fast power calculation             - calculates power in O(log n)"
   ${1,int} fastpow($1 a, $1 n) {
       $1 res = 1;
       while(n)
           if (n & 1) { res *= a; --n; }
           else {a *= a; n >>= 1; }
       return res;
   }
   $0
   

   It is very convenient to place a $0 tabstop at the end of the method. For more about tabstops and mirros, please check the UltiSnip's documentation.