what's wrong with the queue, 20mins have passed and my code is still in queue?
There was no contests today and no rejudging, so why so long queues
# | User | Rating |
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1 | tourist | 3880 |
2 | jiangly | 3669 |
3 | ecnerwala | 3654 |
4 | Benq | 3627 |
5 | orzdevinwang | 3612 |
6 | Geothermal | 3569 |
6 | cnnfls_csy | 3569 |
8 | jqdai0815 | 3532 |
9 | Radewoosh | 3522 |
10 | gyh20 | 3447 |
# | User | Contrib. |
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1 | awoo | 161 |
2 | maomao90 | 160 |
3 | adamant | 156 |
4 | maroonrk | 153 |
5 | -is-this-fft- | 148 |
5 | atcoder_official | 148 |
5 | SecondThread | 148 |
8 | Petr | 147 |
9 | nor | 144 |
9 | TheScrasse | 144 |
So I was looking for some probability problems And I stumbled upon 398B - Красим стену, I realized it had no rating, which was weird in my opinion because it was a normal Div1 without anything special, I checked the whole contest and no problems had a rating, I thought it's my get rating scripts' bug, but when I enabled tags in the setting there were no rating tags? Is this a bug? MikeMirzayanov
Hello, following my previous blog, I'm adding the new problems I found interesting/teaching, so let's get into the problems
Note: these problems are mostly for the range of [pupil, expert] level, an average specialist with a bit of sweat will be able to solve them all
1549C - Web of Lies
553A - Kyoya and Colored Balls
333D - Characteristics of Rectangles
1873E - Building an Aquarium
1873H - Mad City
363D - Renting Bikes
358D - Dima and Hares
1624D - Palindromes Coloring
1928C - Physical Education Lesson
1918E - ace5 and Task Order
1834D - Survey in Class
1931F - Chat Screenshots
1931D - Divisible Pairs
1931G - One-Dimensional Puzzle
343C - Read Time
551C - GukiZ hates Boxes
1904D1 - Set To Max (Easy Version)
1904D2 - Set To Max (Hard Version)
1705D - Mark and Lightbulbs
1930C - Lexicographically Largest
1930D1 - Sum over all Substrings (Easy Version)
1930D2 - Sum over all Substrings (Hard Version)
1932C - LR-remainders
1926G - Vlad and Trouble at MIT
20A - BerOS file system
782B - The Meeting Place Cannot Be Changed
573B - Bear and Blocks
965D - Single-use Stones
1629D - Peculiar Movie Preferences
1923C - Find B
1251D - Salary Changing
1923D - Slimes
378C - Maze
1933E - Turtle vs. Rabbit Race: Optimal Trainings
1930E - 2..3...4.... Wonderful! Wonderful!
1272D - Remove One Element
1909B - Make Almost Equal With Mod
1909C - Heavy Intervals
1909D - Split Plus K
1909F1 - Small Permutation Problem (Easy Version)
480C - Riding in a Lift
380C - Sereja and Brackets
1365D - Solve The Maze
607B - Zuma
1941G - Rudolf and Subway
1077D - Cutting Out
1610C - Keshi Is Throwing a Party
1856C - To Become Max
1862F - Magic Will Save the World
1948D - Tandem Repeats?
1462E1 - Close Tuples (easy version)
1462E2 - Close Tuples (hard version)
237C - Primes on Interval
231C - To Add or Not to Add
1061C - Multiplicity
1486C1 - Guessing the Greatest (easy version)
1486C2 - Guessing the Greatest (hard version)
1569D - Inconvenient Pairs
The problems aren't in any specific order but higher problems may be a bit easier
These problems' requirements are intermediate dp, binary search, pure logic, algorithmic thinking, and math.
and I've solved all of them so feel free to check my submissions if u wanted
As we all have noticed it's been a while that tourist wasn't doing as well as before in the contests and had dropped to the rank 13, but yesterday he crushed the Div1 solving to E2 and got the rating change of +125.
When I started cp he was the first in cf, and seeing him dropped was a weird thing, tourist the legend of legends dropped to 13th, but he proved us again that is the best by re-getting first.
Congratulations
Hello cf community, in this blog I tried to gather binary search problems that are worth solving and maybe makes you learn it better, if there exist any blog tell me I'll remove this
1486D - Максимальная медиана
1486C1 - Найти наибольшее (простая версия)
1486C2 - Найти наибольшее (сложная версия)
883I - Photo Processing
1707A - Дореми и её IQ
1945E - Бинарный поиск
1623C - Сбалансированные кучки камней
1117C - Волшебный корабль
1862F - Волшебство спасёт мир
1856C - Стать максимумом
1610C - Кеши устраивает вечеринку
1077D - Вырезание массива
1730B - Собрание на прямой
1622C - Присвоить или уменьшить(doesn't need binary search)
1073C - Вася и робот
1923D - Слизни
782B - Место встречи изменить нельзя(recommended to solve)
343C - Время чтения
551C - GukiZ ненавидит коробки
1698D - Угадывание неподвижной точки
333D - Характеристики прямоугольников
1902D - Запросы робота(not binary search focused, just a tool)
1853C - Набор Ntarsis
1843E - Слежка за отрезками
251A - Точки на прямой
371C - Гамбургеры
372A - Весело считать Кенгуру
460C - Подарок
448D - Про таблицу умножения
670D2 - Волшебный порошок - 2(thanks to Arpa)
codechecf QHOUSE (also thanks to arpa)
1520F1 - Угадай K-й ноль (простая версия)
1520F2 - Угадай K-й ноль (сложная версия)
These problems are mostly specialist/expert level based but everyone can solve them, have fun and Hope you enjoy them
Peace
In a weird high school, there are $$$n$$$ students, and the school principal Mr. X wants to make students happy so he decides to throw a couples' party.
In this high school, between every 2 person, there can be 4 types of relationships:
1: they love each other
2: The first loves the second but the second doesn't
3: The second loves the first but the first doesn't
4: they don't like each other
At this party, people will be grouped into Pairs of couples.
The relationship between them determines the happiness of a pair:
type 1: happiness 2, type 2,3: happiness 1, type 4: happiness -1
if a person gets left out(I.E n is odd) there will be a -2 happiness for him
Since Mr. X is a happy person he wants to maximize the sum happiness of the party. Since he is a busy person He asks you to do that
Input Format
In The First Line, there will be one integer $$$n$$$: $$$n$$$, ($$$1 \leq n \leq 10^5$$$) the number of people at the party. In the Second line will be $$$m$$$, the number of people who love a person ($$$1 \leq r \leq 10^5$$$)
In the following $$$m$$$ lines there will be a format: two indexes $$$i$$$, $$$j$$$ meaning the person $$$i$$$ loves the person $$$j$$$. (Two-sided love will be given in 2 separate lines, if there isn't a directed edge between 2 people their relationship is type 4)
Output Format In the only line of the output, print the maximum happiness of the party
So today I came up with this problem and actually got stuck in solving it. Appreciate any helps
Hello, In this blog, I've tried to share my opinion on how to get good at dp problems, so stick to the end
in my opinion, dp is 85% thinking on paper, 10% thinking in your brain and 5% implementation.
so if you approach a dp problem always have pencil and paper and USE THEM another thing is just solving the DP problems in combinatorics.
What do I mean?
Question. 1 Given $$$n$$$, generate the set $$$s$$$ s.t $$$s = {1, 2, 3, 4, ..., n-1, n}$$$ then
count the number of subsets, where those elements in the set have at least 1 element in between them;
for example, $$$n = 8$$$ then $$$s = {1,2,3,4,5,6,7,8}$$$, one valid subset would be $$${1,4,8}$$$.
let $$$f_n$$$ be the solution of $$$n$$$, now let's backtrace,
$$$n$$$ comes -> $$$n-1$$$ won't come, but $$$n-2$$$ can be in the subset, but necessarily isn't so $$$f_{n-2}$$$
$$$n$$$ doesn't come -> $$$n-1$$$ can be so $$$f_{n-1}$$$
giving us $$$f_n = f_{n-1} + f_{n-2}$$$
Question. 2 Same as Question 1 but should have at least 2 elements in between them
let $$$f_n$$$ be the solution of $$$n$$$, now let's backtrace,
$$$n$$$ comes -> $$$n-1$$$ won't come, neither $$$n-2$$$ will, but $$$n-3$$$ can be in the subset, but necessarily isn't so $$$f_{n-3}$$$
$$$n$$$ doesn't come -> $$$n-1$$$ can be so $$$f_{n-1}$$$
giving us $$$f_n = f_{n-1} + f_{n-3}$$$
Question. 3 Same as Question 1, Let's stop it
Let $$$a_n$$$ be the number of binary strings with ab, s. t no three consecutive characters are a.
find a recursive formula for $$$a_n$$$.
So the current string with length $$$n$$$ either was another string with length $$$n-1$$$ with the b at the end,
or was $$$n-2$$$ with ba at the end or $$$n-3$$$ with baa at the end. So $$$a_n = a_{n-1} + a_{n-2} + a_{n-3}$$$
Since the problems I've are in Persian and translating them would be a pain, Message me and I'll send them to you if you want but the translation is on you
Hope this Helped
Hello, CF community, I found this 1700*-ish problem, can somebody help?
Given $$$n$$$, $$$d$$$ positive integers, and the array $$$a$$$ with length $$$n$$$
for each $$$i$$$ s. t $$$1 \leq i \leq n$$$
Find the maximum j s. t $$$\vert{a_i - a_j}\vert \leq d$$$
Input format:
Integers n,d: $$$1 \leq n \leq 1e5, 1 \leq d \leq 1e9$$$
In the next line given $$$n$$$ integers representing $$$a_1$$$, $$$a_2$$$, ..., $$$a_{n-1}$$$, $$$a_n$$$
Output format:
In single line for each $$$1 \leq i \leq n$$$ output the corresponding $$$j$$$
if there is no corresponding $$$j$$$ output -1
I'd appreciate a solution without any kind of advanced data structure(___Trees, ___Arrays, etc)
Thanks for any help
Hello CF community, in this blog post I tried to gather the Questions I've solved and enjoyed them most of them are really teaching and worth spending hours of time on them Hope you enjoy
EDIT: Part 2 added, link
1418C - Mortal Kombat Tower
1311D - Three Integers
474D - Flowers
343C - Read Time
1918D - Blocking Elements
515C - Drazil and Factorial
1156C - Match Points
1853C - Ntarsis' Set
1843E - Tracking Segments
1843F1 - Omsk Metro (simple version)
1884D - Counting Rhyme
1884C - Medium Design
372A - Counting Kangaroos is Fun
455A - Boredom
1886D - Monocarp and the Set
1624D - Palindromes Coloring
448D - Multiplication Table
1092D1 - Great Vova Wall (Version 1)
479E - Riding in a Lift
1907E - Good Triples
1520F1 - Guess the K-th Zero (Easy version)
1520F2 - Guess the K-th Zero (Hard version)
1201C - Maximum Median
1374D - Zero Remainder Array
1922D - Berserk Monsters
1705C - Mark and His Unfinished Essay
380A - Sereja and Prefixes
747F - Igor and Interesting Numbers
1920D - Array Repetition
1920C - Partitioning the Array
831C - Jury Marks
1398C - Good Subarrays
1000C - Covered Points Count
1526C2 - Potions (Hard Version)
368B - Sereja and Suffixes
1324D - Pair of Topics
520B - Two Buttons
1901D - Yet Another Monster Fight
1919C - Grouping Increases
1574C - Slay the Dragon
1076C - Meme Problem
1349A - Orac and LCM
1358C - Celex Update
1458A - Row GCD
1539D - PriceFixed
1537E1 - Erase and Extend (Easy Version)
1497C2 - k-LCM (hard version)
1285C - Fadi and LCM
Note that to solve these problems you need no knowledge except:
9th grade math, a little bit number theory, sorting, elementary dp, elementary bs, set, stack, queue, map
Good luck and hope you enjoy them
EDIT: I added maybe a few problems, I ran out of beautiful problems, unfortunately, maybe suggest in the comments and I'll add them
Guys a question: do u want me to include recent contests as well?
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