10 Essential C++ Tricks for Beginners in Competitive Programming

Competitive programming requires efficient and concise coding techniques to solve complex problems under time constraints. In this blog post, we will explore 10 essential C++ tricks that can help beginners in competitive programming. These tricks will enhance your code readability, improve performance, and provide a solid foundation for solving algorithmic challenges.

here we go >>>

for ( i = 0 ; i < 10 ; i++)

i=0 .  Include All Standard Libraries in One Go

By using #include stdc++.h, you will be able to add all standard libraries to your project without having to individually include them. A programming competition, where time is at a premium, is a perfect example of when this is useful.

As an example (and there are many more), you can replace the following:

#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <stack>
#include <set>
#include <queue>
#include <map>

With this:

#include <bits/stdc++.h>

Keep in mind

• <bits/stdc++.h> contains a lot of header files that you might not need to use in your project. This can increase compilation time.

• <bits/stdc++.h> is not the standard header file of the GNU C++ library. Non-GCC compilers might struggle to compile. However, most of the time this won't happen!

i =1 . Using Macros for Shortcuts:

cpp
#define rep(i, n) for (int i = 0; i < (n); ++i)

Macros allow you to define shortcuts for commonly used code snippets. The rep macro simplifies the process of writing a loop that iterates from 0 to n-1. Usage: rep(i, n) { /* code here */ }.

i =2. Type Aliases with typedef or using:

cpp
typedef vector<int> vi;
using ll = long long;

Create aliases for complex data types using typedef or using. The vi alias represents a vector of integers, and ll represents the long long data type.

i = 3 . Eliminate Repetitive Code with Macros:

cpp
#define sz(x) ((int)(x).size())

The sz macro calculates the size of a container. It helps avoid repetitive code like container.size() and can be used as sz(container).

i = 4 . Faster Input/Output using scanf and printf:

cpp
int n;
scanf("%d", &n);
printf("The value of n is: %d\n", n);

For faster input/output operations, use scanf and printf instead of cin and cout. Format specifiers are used to read or write variables.

i = 5 . Bitwise Operations for Efficient Manipulation:

Bitwise operations (&, |, ^, <<, >>) manipulate individual bits in an integer. They are useful for various operations involving bits, such as bitmasking and checking odd or even numbers.

sort(arr, arr + n, greater<int>());

You can customize sorting behavior by providing a comparator function or object. This example sorts an array arr in descending order using the greater<int>() comparator.

i = 6 . Utilize the Standard Template Library (STL):

The STL provides powerful data structures and algorithms. Familiarize yourself with containers like vectors, sets, and maps, as well as algorithms such as sorting, binary search, and more.

i = 7 . Precompute Values for Performance:

If you have computations that can be precalculated, store the results in an array or container to avoid redundant calculations during program execution. This technique can significantly improve performance.

i = 8 . Mind Integer Overflow :

Be cautious of potential integer overflow when dealing with large numbers. Consider using larger data types like long long int or int64_t if the range of values exceeds the limits of int. The range of int typically spans from -2,147,483,648 to 2,147,483,647 and range of long long int typically spans from approximately -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807.

i = 9 . Practice Problem-Solving:

Lastly, the most effective way to improve in competitive programming is to practice regularly. Solve a variety of problems to enhance your coding skills and familiarize yourself with different algorithms and data structures.

Conclusion:
These 10 essential C++ tricks for beginners in competitive programming will provide you with a solid foundation to tackle algorithmic challenges efficiently. Remember to focus on understanding the underlying concepts and algorithms, and continuously strive to improve your problem-solving skills.

 

Happy coding!