LoooLOOOLOLoloOL. Rofl. Lmao. You are stupid. If you truly believe in your words then that means you're kinda illiterate.

1)Java forbids to make stupid mistakes.

2) TL;DR: Python's functional paradigm is cool

Compared to Python, unless you want to couple everything into one unreadable line, then C++ should not be very long.

Square matrices multiplicationin C++:

matrix mul(matrix& a,matrix& b)
{
    int n=a.size();
    matrix c(n,row(n,0));
    for (int i=0;i<n;i++)
        for (int j=0;j<n;j++)
            for (int k=0;k<n;k++)
                c[i][j]+=a[i][k]*b[k][j];
    return mul;
}

In python:

def mul(a,b):
    n=len(a)
    def cell(i,j):
        return sum([a[i][k]*b[k][j] for k in range(n))
    def row(i):
        return [cell(i,j) for j in range(n)]
    return [row(i) for i in range(n)]

Very readable code.

The list of 20 first even numbers in C++:

vector<int> v(20);
for (int i=0;i<20;i++)
    v[i]=i*2;

In python:

[2*i for i in range(20)]

I hope that helps you to overcome your illiterateness.

Usually "Not everyone knows C++" is the reason.

-1

Downvote me if that's what it takes to get the message through but your questions are stupid, your examples are stupid, your blog is stupid.

Why would anyone use Python or Java in Codeforces?

Choosing a programming language is the choice of the programmer. Some people like efficiency, C/C++/Assembly. Some people like correctness, Java. etc etc etc. Every language exists because there's probably something unique to it. Different people like to have different options. If I like to have my code free from any and all runtime errors on the very first go, I'd choose Java. It will not let me make mistakes unlike C++ assuming that I'm always right. I could go on and on and on ranting about this for different languages, but people who usually pose such questions are stupid and giving enough examples won't do any good.

You need to understand that C++ isn't C++ because of its speed, pbds or direct memory access or any other feature. Same goes for Python, Java, Lisp, Pearl, Mathlab, C, Javascript, Assembly, Scala, C#, etc. If features were to be the defining factor of a language, I bet there'd already be one incorporating all programming paradigms by now, but there isn't, not that I know of, and so you must respect programmers of all languages and the languages as well and leave their choice to be theirs.

It's like saying "Yes, the british almost ruled over the entire world, so everyone should know how to speak english". Or more like, "Everyone should speak language $$$X$$$ because it has the most letters, most number of meaningful words and in general, it's considered the best because many people like to use it. So, you should stfu and speak in this language because your language doesn't have some features like ours".

To become grandmaster.

Petr also switched from Java to C++.

The factor you leave out that I think is most important is how easy it is to debug. I spend most of my time in contest debugging errors in my solution. With C++ it takes a lot of experience to avoid common mistakes, and a lot of time to track down even simple typos. Both Java and Python have a major advantage over C++ in this area. I've wasted many minutes in contest dealing with a segmentation fault.

The only real advantage C++ has over Java and Python is that the solutions execute faster. But if your solution is fast enough anyways, why not use Java/Python if they are your favorite language. You only really need C++ for solution where efficiency is really important.

That said, for me, Java takes way too long to type simple things, and Python is too slow. I've been thinking of switching to Kotlin from C++ after the last Kotlin Heroes though because debugging was way easier, some other syntax was more natural, and it has better support for a more functional style.

Not sure why all people in the comments seem to have taken offense at this blog, seemed like a fairly reasonable question to me. Something I've wondered at certain times, too.

Python is much more convenient than C++ for many things, but it's often way too slow. For real-life purposes it is often a great choice because the abundance of amazing libraries (many of them implemented in C, so fast) along with a neat syntax make it really easy to get stuff working quickly. For competitive programming, however, I personally find it impossible to overcome the speed difference, and you can't use public libraries either. However, many people start out by learning Python, so they naturally try to use that.

Java, as mentioned by other people, has the great side of preventing many common mistakes and also making debugging much easier — for example accessing out of the bounds of an array will throw a runtime exception and tell you where exactly its thrown from, rather than just crashing as it would in C++. The speed compared to Python is much better, but still noticeably slower than C++. Additionally, the memory consumption can be much higher if you use the Java-way of doing things (i.e. structures of boxed primitives). My opinion on Java is that if one is very comfortable with it, it is a much more viable option for competitive programming than Python.

So in summary, you seem to hold a view that these languages are somehow inferior to C++, which is why I suspect people are reacting harshly. While I personally agree (and statistically the community at large does too) that C++ is best for competitive programming, these languages have various advantages that some people deem worthy enough to sacrifice speed.

To be honest if you're completely comfortable with all three languages, then picking the right one for each problem would be much more efficient than writing everything in C++.

Auto comment: topic has been updated by duckladydinh (previous revision, new revision, compare).

First of, I don't use Python for competitive programming (mostly because of the huge speed difference). But I write Python for a living.

Some of the advantages that you have with Python: shorter, easier, larger standard lib, safer, dynamic typing

Here's one code comparison.

std::vector<int> v{1, 2, 5, 4, 3}; 
std::sort(v.begin(), v.end());   
auto it = std::find(v.begin(), v.end(), 4);     
if (it != v.end()) {                  
    int idx = v.end() - it;          
}

vs.

v = [1, 2, 5, 4, 3]
v.sort()
if 4 in v:
    idx = v.index(4);

Even though the actual task is very easy, the C++ code require understanding of quite a few hard concepts, like iterators, initializer_lists, templates or how the memory layout of vectors work. On the other hand the Python code is very easy and short, especially since lists are built in types and the many nice helper functions.

In general the libraries of Python are a lot more powerful than C++'s. What to split a string by spaces: "a bc def".split() (I dare you to do that in a simple way in C++!) Want to iterate over all combination (without repeats): for u, v in combinations(lst, 2):. Want to speed up a function using memoization: just apply a decorator @lru_cache, Need big integers, high precision floats or fractions, they are in the standard lib. ...

Compiler support is also a lot better (especially for inexperienced C++ user). And the language is safer. Ever had a multi-page error message in C++, because of you had a template parameter wrong, or because you forgot to implement the comparison operator. Python will tells you the problem concise. Ever had to hunt down a bug, because you accessed unallocated memory and C++ just gave you garbage values and didn't crash. With Python that will not happen.

Also, not everybody learns C++ at university. E.g. at my university you only learn it in a computer science program, if you are doing an optional game programming course (however you also don't lean Python). And lots of teachers still teach very ancient C++98 or even older. Just look around at Codeforces and see thousands of complete ugly C++ submission.

But all the nice stuff that comes with Python, it also has disadvantages. And the main one is speed. So I would still recommend C++ for anybody who wants to get seriously into competitive programming. But the most of the arguments that you make against Python are not true.

Auto comment: topic has been updated by duckladydinh (previous revision, new revision, compare).

Auto comment: topic has been updated by duckladydinh (previous revision, new revision, compare).

Why I use Python is because it's easier. That's it. It comes with some disadvantages as well, like being slow and recursion limit till 30000 or so. But at this stage it helps me in focusing on question and it's solution more than it's syntax and other things. I've used Java/C++ as well but right now I feel I'm most efficient while coding in Python.

My old blog on D language usage in competitive programming. Shows how the experience differs from C++ mostly, because C++ is the "default language" for competitive programming. Relevant because many of the grievances with C++ and joys with other languages, which make people choose the latter, are similar. Be it Python or Java or otherwise.

My reason for using java: Never undefined behaviour. C++ sucks at that.

My reason to use Java is that I want TLE due to sorting.

I mostly use C++ but I switch to python sometimes when there are a lot of string manipulations involved. E.g the solution to 200D - Programming Language is relatively short in python 78036294 but seems like a nightmare to implement in C++. Also python can be useful for bigint problems but I haven't really encountered many.