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1.

Altitude

Last visit:  2 years ago
Registered:  9 years ago
2.
By E869120, 5 weeks ago, In English
Serious Altitude Issue in IOI 2025 Hello, CodeForces! Today, I would like to discuss about an issue of IOI 2025 venue. The venue of IOI 2025 is still not officially announced, but according to [the website](https://ioi2025.bo/), IOI 2025 will be held in La Paz, Bolivia. <img src="https://i.ibb.co/PFjkSF1/1.png" alt="1" border="0" width="40%"></img> As you know, La Paz is one of the highest cities in the world. For example, the center of La Paz is at 3600 meters above the sea level, and [El Alto International Airport](https://en.wikipedia.org/wiki/El_Alto_International_Airport), which is the nearest large airport from La Paz, is at 4100 meters above the sea level. Therefore, **altitude sickness can be a big concern.** I think that even the following things can happen: * 20% of the contestants collapsed at the airport, and they were even unable to reach hotels * 30% of the contestants collapsed during hotel stay, opening ceremony, practice sessions and excursions, and they were unable to participate in the c...
Serious Altitude Issue in IOI 2025, La Paz, is at 4100 meters above the sea level. Therefore, **altitude sickness can be a big concern, above the sea level. Therefore, **altitude sickness can be a big concern.** I think that even the, medal because I often suffer altitude sickness at 2500 meters above the sea level., -elevated, like altitude of 100 meters or 200 meters., Are there any tips or any ways of practice to get used to high altitude?

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3.
By willy108, history, 14 months ago, In English
Teamscode Spring 2023 Editorial This is the editorial for a recent contest [Teamscode](https://www.teamscode.org/). The problems are open for upsolving on [this gym](https://codeforces.com/gym/104287). Problems were prepared by [user:oursaco,2023-04-06], [user:dutin,2023-04-06], [user:thehunterjames,2023-04-06], [user:Bossologist,2023-04-06], [user:Esomer,2023-04-06], and me. ### [A. What do you do when the contest starts? Are you busy? Will you solve Bingo?](https://codeforces.com/gym/104287/problem/A) <spoiler summary = "Editorial"> <spoiler summary = "Are you busy?"> 1. WorldEnd/SukaSuka 2. Bocchi the Rock </spoiler> <spoiler summary = "No Sweep"> 1. Thomas </spoiler> <spoiler summary = "Multiplication Table"> 1. Lycoris Recoil </spoiler> <spoiler summary = "Greatest Common Multiple"> 1. Bokuben </spoiler> <spoiler summary = "A Certain Scientific Tree Problem"> 1. A Certain Scientific Railgun </spoiler> <spoiler summary = "Two and Three"> 1. Quintessential Quintluplets...
counter for the number of times the altitude increases consecutively. Make sure to reset this counter, for point $p$ excluding points below the fog altitude (given that the fog is not above $p$). Note, right and maintain a counter for the number of times the altitude increases consecutively. Make sure, }); // used to iterate in increasing altitude }, altitude at least as high as $p$. There are a couple ways of doing this, but using a stack, we can

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4.
By Xellos, 11 years ago, In English
Codeforces Trainings Season 1 Episode 4: Editorial ### A. Arrangement of RGB Balls (difficulty: easy) If, among 3 consecutive balls, there are no two of the same color, then there's exactly one ball of every color among them. Thereforce, the sequence is determined by the order of the first 3 balls. Imagine these are RGB; then, the sequence continues as RGBRGBRGB... There are only $3!=6$ possible initial triples, so we can try all the sequences defined by them, and for every one of them, check if it can be constructed. [cut] When is it possible to construct such a sequence? Take the initial triple to be "GRB", for example (the idea for other triples is analogous). It's clear that the sequence is "GRB" repeated some $K$ times, and after that, there are the first 0, 1 or 2 balls from that triple (for example, "GRBGRBGR" or just "G"). It's clear that $K=min(R,G,B)$. So it's possible to construct iff $1\ge G-K \ge R-K \ge B-K$. Testing the existence of any sequence can be done in $O(1)$ time like this. There are $O(1)$ possib...
distance from line $AB$ is also the $S$ altitude of triangle $ABS$, which is also 2x the area of $ABS, possible cases: 1. the feet of said altitude intersects line **segment** $AB$, 2. it doesn't, but, $ is also the $S$ altitude of triangle $ABS$, which is also 2x the area of $ABS$ / distance of $A

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5.
By mfv, history, 8 years ago, In English
Experimental Educational Round: VolBIT Formulas Blitz Editorial #### [A. Again Twenty Five!](http://codeforces.com/problemset/problem/630/A) The problem of getting the last two digits is equivalent to the problem of getting the number modulo $100$. So we need to calculate $5^{n} \mod 100$. According to [cut] the rules of modular arithmetic $(a \cdot b) \mod c = ( (a \mod c) \cdot (b \mod c) ) \mod c$ So $5^{n} \mod 100 = ((5^{n-1} \mod 100) \cdot 5) \mod 100$ Let's note that $5^2=25$. Then $5^3 \mod 100 = ((5^2 \mod 100) \cdot 5) \mod 100 = (25 \cdot 5) \mod 100 = 25$ $5^4 \mod 100 = ((5^3 \mod 100) \cdot 5) \mod 100 = (25 \cdot 5) \mod 100 = 25$ And so on. All $5^n \mod 100$ are equal to $25$ for all $n \ge 2$. So to solve the problem one need to just output `25`. There is no need to read $n$. #### [B. Moore's Law](http://codeforces.com/problemset/problem/630/B) Every second the number is multiplied by $1.000000011$. Multiplication several times to the same number is equivalent to exponentiation. So the formula i...
equal to $l_n$, $OB$ is the altitude of $AOC$ triangle. As the polygon is a regular one $OA=OC$, $AOC, $ is the altitude of $AOC$ triangle. As the polygon is a regular one $OA=OC$, $AOC$ triangle is a

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6.
By Hikari9, history, 8 years ago, In English
Two-liners for triangle centers using Barycentric coordinates Recently, I created a [blog entry](http://codeforces.com/blog/entry/22175) about using C++ `std::complex` as an alternative to points for computational geometry. We will now apply this technique for more geometry for C++! Triangle centers are important for they create a connection between triangles, circles, and angles in geometric construction. But the classical way to determine them is a little hassle to either derive, or code. For example, we can get the circumcenter by constructing two perpendicular bisectors and intersecting them. [Math for dummies](http://www.dummies.com/how-to/content/how-to-find-the-incenter-circumcenter-and-orthocen.html) provides a brief explanation of some triangle center formulae if you want to know what I'm talking about. But can we generalize the way to get ALL kinds of triangle centers? Barycentric Coordinates ----------------------- Barycentric coordinates uses a kind of coordinate system through three vertices of the triangle as basis. ...

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7.
By Killever, 13 years ago, In English
CF81 hacking ,problem A To all people whose confused about hacking his/her &nbsp;first problem or faild system test because of&nbsp;<span class="Apple-style-span" style="font-family: verdana, arial, sans-serif; font-size: 14px; background-color: rgb(255, 255, 255); ">precision issues.i also faild system test :(</span><div><font class="Apple-style-span" face="verdana, arial, sans-serif"><span class="Apple-style-span" style="font-size: 14px;">accuracy in programming is very very important so let me tell you a short story .&nbsp;<br></span></font><div><div><span class="Apple-style-span" style="font-family: verdana, arial, sans-serif; font-size: 14px; background-color: rgb(255, 255, 255); ">do you hear about "</span><span class="Apple-style-span" style="background-color: rgb(255, 255, 255); "><a href="http://en.wikipedia.org/wiki/Ariane_5_Flight_501">Ariane 5 rocke</a></span><span class="Apple-style-span" style="font-family: verdana, arial, sans-serif; font-size: 14px; background-color: rgb(255, 255, 255); ">" &n...
the flight sequence, at an altitude of about 3700 m, the launcher veered off its flight path, broke, altitude of about 3700 m, the launcher veered off its flight path, broke up and exploded.

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8.
By qzqzgfy, history, 8 years ago, In English
O. Arrow (630 O) O. Arrow time limit per test0.5 seconds memory limit per test64 megabytes inputstandard input outputstandard output Petya has recently started working as a programmer in the IT city company that develops computer games. Besides game mechanics implementation to create a game it is necessary to create tool programs that can be used by game designers to create game levels. Petya's first assignment is to create a tool that allows to paint different arrows on the screen. A user of this tool will choose a point on the screen, specify a vector (the arrow direction) and vary several parameters to get the required graphical effect. In the first version of the program Petya decided to limit parameters of the arrow by the following: a point with coordinates (px, py), a nonzero vector with coordinates (vx, vy), positive scalars a, b, c, d, a > c. The produced arro...
of a triangle and a rectangle. The triangle is isosceles with base of length a andaltitude of length, rectangle. The triangle is isosceles with base of length a and altitude of length b perpendicular to

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9.
By DottedCalculator, 15 months ago, In English
Every problem I ever made In this post, I want to go over each of my problems. I got this idea from antontrygubO_o and flamestorm. <table> <tr> <td> Number </td> <td> Problem Statement </td> <td> Source </td> <td> Comments </td> </tr> <tr> <td> 001 </td> <td> In right triangle $ABC$, we have $\angle B=90^{\circ}$. If $AC=18$ and the length $x$ of the altitude from $B$ to $AC$ satisfies $$x^2-51x+279=0,$$ then the maximum possible value of the area of $ABC$ can be expressed in the form $\frac{a+b\sqrt c}d$ for integers $a$, $b$, $c$, and $d$, where $\gcd(a,b,d)=1$, $c$ is squarefree, and $d$ is positive. Compute $a+b+c+7d$. </td> <td> CNCM PoTD 07/03/2021 </td> <td> The answer is not $665$. </td> </tr> <tr> <td> 002 </td> <td> Let $n$ be a positive integer such that $n=a^{665}m$, where $a$ is as large as possible. Then, define $\psi(n)=\mu(m)$, where $\mu(n)=0$ if $p^2\mid n$ for some $p$, and $\mu(n)=(-1)^k$ if $n$ is squarefree and has $k$ prime factors. Find $$\sum_{i=1}^n\...
=90^{\circ}$. If $AC=18$ and the length $x$ of the altitude from $B$ to $AC$ satisfies $$x^2-51x+279

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10.
By Rundc09, history, 4 years ago, In English
How can coders have high ranks and high scores? I have a low altitude and I am about to become a newbie.....How can I have higher ranks and higher scores?Thanks!
I have a low altitude and I am about to become a newbie.....How can I have higher ranks and higher

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