International Olympiad in Informatics

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NaN.

discussion

Need help For INOI

I need some help about what exactly should I do for inoi

My prob is i am confused about which dp topics to do and which to not. For example dp with bit masking is required or not. Also there were many many topics on geeks for geeks and i couldnt get which ones to do as time is limited. It is nowhere mentioned on iarcs etc. Which questions of dp go beyond inoi level? Also is there a need to do segment trees ( i have no idea about it).

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Category: International Olympiad in Informatics

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Taksh Pratap SinghProgrammer: interest… · 3y

This might help: International Olympiad in Informatics: Path to Gold

This playlist is mostly based on IARCS syllabus and previous years' papers' trends.

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NaN.

tutorial

Introduction to Graphs (and how to represent them)

I recommend watching the following videos for learning about graphs. These are really well made videos and he covers a lot in these short videos, so if you feel overwhelmed, use the rewind and pause buttons.

Introduction to Graphs

What are graphs? What are different types of graphs (directed and undirected, trees and DAGs, etc)? And examples of using them to model web links, flights between cities, and other things.

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Category: International Olympiad in Informatics

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Fine information, many thanks to the author. It is puzzling to me now, but in general, the usefulness and importance is overwhelming. Very much thanks again wise essays and best of luck!

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Keshav DhandhaniaIOI medalist · 4y

Yes. It is usually an object in real world applications. But an index can always represent an object, because it denotes the position of the object in an object array.

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Soumyadeep Roy4y

In the most of the text/video tutorials,vertices are always( as far as I've noticed) represented by integers ( from 0 to any positive integer). Is this always the case?? I ponder if we're dealing with real life,then vertices would be an object,right??

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NaN.

discussion

Leaf Eaters (ICO online judge)

For those of you who haven't solved this problem, this is one of the best problems from which you can learn how limitations of memory and time can make an easy problem, difficult to solve!

Just when I obtained the accepted sign after several trials, I was quite disappointed that I got a worst case running time of 1.98 s . So I headed over to Keshav's github repository and when I tried out the solution posted, it gave me a worst case running time of 0.024 s. Wow! Now that's a huge improvement. I really wanted to upgrade my arsenal with the procedure that had been used, but to my dismay I couldn't understand how it actually works. It would be great if someone posted the technique and procedure employed in solving the problem in the link attached above!

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ioi-training/LEAFEAT.c at master · keshav57/ioi-training · GitHub

https://github.com/keshav57/ioi-training/blob/master/ZCO/LEAFEAT.c

IARCS Problem Archive

http://opc.iarcs.org.in/index.php/problems/LEAFEAT

Category: International Olympiad in Informatics

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Desmond Willowbrook9w

I find this solution to be the easiest to understand:

It employs the Inclusion-Exclusion Principle, but the main recursive function is much simpler to understand.

#include <bits/stdc++.h>

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Taksh Pratap SinghProgrammer: interest… · 3y

This is the official explanation for the problem: Indian National Olympiad in Informatics Btw, this problem was part of the 2004 INOI

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Aadesh Salecha4y

Yeah, your solution seems a lot more intuitive, thanks for sharing. :)

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NaN.

discussion

What is the best way to represent adjacency lists in C++98

INOI is coming up soon, and seeing that only C++98 was provided in ZCO, I won't be surprised (but would be upset) that they provide the same in INOI.

Normally I represent undirected graphs as an unordered_map of vectors, like this:

unordered_map <int, vector <int>> graph;

For directed graphs, I may use an unordered_map of unordered_maps to store the weights.

However, what is the best way to do so in C++98, especially for sparse graphs. Do I have to resort to something like: int graph[n][n] which would consume quite a lot of space, as it is basically just an adjacency matrix.

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Category: International Olympiad in Informatics

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Bethany Woodward12w

Discussion and all matter is fit for the title for the sores for the field. Improvement of the team and type for me for the content. The link displaced for the approval of the true way for the turns for the ways for all offer for the count and dumping of the sights.

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Filip Došilović4y

I know it's already to late, but I represent adjacency list as:

// global variable

vector<int> adjacency_list[MAX_NUMBER_OF_NODES]

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Sudhansu Mishra4y

Great! If that happens, maybe I won't need to use complex pointers without compromising on runtime.

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NaN.

tutorial

Breadth-first search and Depth-first search

Video for concept and walkthrough

First, let's watch a slow-paced easy-to-follow walkthrough of the breadth-first search and depth-first search algorithms.

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Category: International Olympiad in Informatics

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good!

ukessays review

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I would like to see it again.

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Sudhansu Mishra4y

EDIT: Correction! it's optimal; sorry!

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NaN.

discussion

Periodic Strings (INOI 2015: India)

Problem in short: Given a positive integer N, find the number of binary strings of length N which are not periodic. Report the answer modulo M. The non-periodic strings of length 3 are 001, 010, 011, 100, 101, and 110. N <= 150,000.

Indian National Olympiad in Informatics (INOI) is round 2 out of 3 (i.e. intermediate) for selection into Indian IOI team.

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https://codechef.com/INOIPRAC/problems/INOI1502

Category: International Olympiad in Informatics

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Desmond Willowbrook9w

Typo:

pStr(N) = 2^d - pStr(d)

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Taksh Pratap SinghProgrammer: interest… · 3y

I coded following these hints but am only getting 90/100. I am getting one subtask of test case 1 wrong. Can you please look into my code and find the error?

Here's my code: Solution: 16727006

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Taksh Pratap SinghProgrammer: interest… · 3y

Thanks for the solution.

I understand why you are using modular exponentiation. But, I have a small doubt: We have to calculate (2^N - repeats)%m. ...

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