Top 5 Competitive Programming Tips for Beginners and Intermediate level Coders || July 2021

You all may have heard the sayings that "Competitive Programming can only be mastered with loads and loads of practice and consistency". Somehow this statement is true but still, it holds a key behind it.  There are certain practices and tricks as well that might give you wings in this journey. We have seen a lot of you struggle and hence we have to come up with a solution. 

In this article, we have added some of the best tips that will surely boost your speed as well as your coding structure. Most of them belongs to CPP(C++) programming language but can also be used as an idea in other languages too. No need to speak that they will help you save much of your time in coding contests also.

1. The GCD function:

In the root directory of C++, it has an inbuilt GCD function and there is no need to explicitly code it. Surely this saves a lot of time during hectic situations in a contest.

Syntax: __gcd(x, y);

Return value : 0 if both x and y are zero,

else gcd of x and y.

2. endl vs \n

ENDL and \N both do the same job of giving a break in the line, but the key is in their working. Using “\n” for adding new line breaks is much faster than using “endl” and also prevents the code to get stuck in TLE (Time Limit Exceeded) error during a programming contest. "\n" breaks the line right beside the string end while the function "endl" flushes the whole stream to give a break.

3. No requirement of loads of header files

Usually, in complex problems, you need to include numerous different header files for various functions and instructions making the process a lot hectic like math, algorithm, iostream, vector etc. But here's a key that we can avoid writing all of them separately and include all of them in a single header file.

#include <bits/stdc++.h>

This library includes almost all the required libraries that we need in contests like algorithm, iostream, vector, and many more. Hence, the need to include anything else gets resolved.

4. Fast IO in C++

Getting TLE is one of the most frustrating things in programming. Often it is recommended to use scanf/printf instead of cin/cout for faster input and output as they are usually faster. However, you can still use cin/cout and achieve the same speed as those in C by adding just two lines in your main() function(before you take any input):

ios_base::sync_with_stdio(false);

cin.tie(NULL);

Note: If you'll use this fast I/O technique, you won't be able to use printf or scanf in your programs. Although you no longer need them.

5. Using string as stack: pushback() and popback()

If you want to apply stack like functionality in your program using string, you don’t need to explicitly declare a stack of characters as a string in C++ but not many coders know this implementation.

Syntax:

string s = “oyetechy”;

s.push_back(‘N’); // pushes a unit character at the end of string, s = “oyetechyN”

s.pop_back(); // pops out a character at the end from the string, s = “oyetechy”.

For now, let's wrap it up guys. We'll be continuing with some more CP specific tips in the next article. Till then keep learning with  OYETECHY.