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tamnd's digital brain — notes, problems, research
41230 notes
Let the degree-$,(t-1),$ combinatorial representation (57) of a positive integer $N$ be written in the form N = \binom{n_t}{t} + \binom{n_{t-1}}{t-1} + \cdots + \binom{n_v}{v}, \qquad n_t > n_{t-1} >...
I can’t produce a correct editorial yet because the actual problem statement for Codeforces 103371M - Yet Another Range Query Problem is missing from your prompt.
The problem statement for “Codeforces 103371K - Three Competitions” is missing from your message, so there isn’t enough information to write a correct editorial.
I cannot safely reconstruct a correct editorial yet because the actual statement of Codeforces 103371J - Periodic Ruler is not visible from the available context.
Let $C(n,t,m)$ denote the graph whose vertices are all $t$-combinations $ctldots c1$ with $$nctcdotsc1ge 0,qquad ct-c1<m,$$ and in which two vertices are adjacent when they differ in exactly one entry, that is, one replacement $cj leftarrow cj'$ preserves strict increase and…
I don’t have the actual problem statement for Codeforces 103371I in your prompt, and I can’t reliably reconstruct it from the title alone without risking inventing details.
I don’t have the actual statement for Codeforces 103371H - Or Machine, and without it any “full editorial” would be guesswork rather than a correct derivation.
The problem statement is missing, so I can’t reliably derive the solution or write a correct editorial for it. “Codeforces 103371G - Lamb’s Respite” alone isn’t enough to reconstruct the task, and guessing would risk inventing constraints, operations, or even the wrong…
We are given a structured coin system with multiple coin types. Each coin type has a value and a weight, and coin values are strictly increasing in such a way that each value is a multiple of the previous one.
I can’t write a correct editorial for this yet because the actual problem statement is missing. “Codeforces 103371F - Hedgehog Graph” alone isn’t enough to reconstruct the graph definition, operations, or required output, and guessing would almost certainly produce a…
The problem statement is missing from your prompt (the sections for Problem Statement, Input, and Output are empty). I can’t safely reconstruct Codeforces 103371D from that, and writing a full editorial without the actual rules would risk inventing details.
We are given several pipeline designs. Each design is a weighted tree over the same set of buildings. Every pipe connects two buildings and has a durability value. For any design, consider any two buildings. There is a unique path between them in the tree.
The editorial request is missing the actual problem statement, so there’s no way to correctly reconstruct the algorithm or constraints.
I can’t write a correct editorial for this yet because the actual problem statement (what “Organizing Beads” is asking, input/output format, constraints) is missing from your message. Right now I only have the title, so any solution would be a guess and very likely wrong.
I can’t reliably write a correct editorial for Codeforces 103372J - Three Competitions because the problem statement isn’t included here, and I don’t have access to the original contest archive from just the ID alone.
Let $C(n,t,m)$ denote the graph whose vertices are all $t$-combinations $ctldots c1$ with $$nctcdotsc1ge 0,qquad ct-c1<m,$$ and in which two vertices are adjacent when they differ in exactly one entry, that is, one replacement $cj leftarrow cj'$ preserves strict increase and…
I can’t write a correct editorial for Codeforces 103372I - Cities Solitaire because the actual problem statement is missing from your prompt.
Let the ternary reflected Gray code on $n$ digits be the sequence of all $n$-tuples $a = a_{n-1}\dots a_1a_0,\qquad a_i \in \{0,1,2\},$ constructed in the standard reflected recursive way, so consecut...
I don’t have the actual statement of Codeforces 103372H - Periodic Ruler in your prompt, so I can’t reliably reconstruct the problem, constraints, or required solution.
I can’t reliably reconstruct Codeforces 103372G (“Or Machine”) from just the name, and I don’t want to invent a problem statement and end up writing an incorrect editorial.
I can’t reliably write an editorial for Codeforces 103372F - Inspection yet because the actual problem statement (what “inspection” refers to, the structure of the input, and what is being optimized or computed) is missing from your prompt.
The problem statement section is empty, so I don’t actually know what “Codeforces 103372D - Equivalent Pipelines” is asking.
I can’t write a correct editorial yet because the actual problem statement is missing. Right now I only know the title “Flowerbed Redecoration”, but there are no details about: - what the input represents - what transformations or constraints exist - what needs to be…
I can write the full editorial in your required format, but I’m missing the actual problem content for CF 103372B - Automatic Sprayer 2.
I’m missing the actual problem statement for Codeforces 103372A - Histogram Sequence 3, so I can’t reliably reconstruct the task, constraints, or edge cases.
Let $C(n,t,m)$ denote the graph whose vertices are all $t$-combinations $ctldots c1$ with $$nctcdotsc1ge 0,qquad ct-c1<m,$$ and in which two vertices are adjacent when they differ in exactly one entry, that is, one replacement $cj leftarrow cj'$ preserves strict increase and…
We are given an undirected graph where each node carries a 16-bit integer value. Every edge contributes a cost equal to the Hamming distance between the two endpoint values, meaning the number of bit positions where the two node values differ.
We are given two short strings, x and y, and we are asked to evaluate the expression x - y exactly as JavaScript would. The key difficulty is that JavaScript does not treat all strings as strings during arithmetic.
We are given a connected network of $n$ locations joined by $n-1$ trails, so the structure is a tree. Each trail connects two locations and carries an integer label.
Let $C(n,t,m)$ denote the graph whose vertices are all $t$-combinations $ctldots c1$ with $$nctcdotsc1ge 0,qquad ct-c1<m,$$ and in which two vertices are adjacent when they differ in exactly one entry, that is, one replacement $cj leftarrow cj'$ preserves strict increase and…
We are maintaining a binary array, where each position is either 0 or 1, under two kinds of operations. One operation flips all bits in a given segment, turning 0 into 1 and 1 into 0.
We are given a process that runs day by day. On day $d$, the process first consumes a fixed amount $p$ of Eatcoins. After paying this cost, it generates income equal to $q cdot d^5$. The algorithm only runs on a day if we can afford the consumption cost at the start of that day.
We are looking at a sequential boarding process for a flight with $n$ seats and $n$ passengers. Each passenger has a fixed assigned seat, but the first passenger is drunk and behaves unpredictably: instead of sitting in their own seat, they pick a random seat uniformly from…
We are given many positive integers, and for each one we must decide how “rich” its proper divisors are. For a number $n$, we consider all its divisors except $n$ itself, sum them up, and compare that sum against $n$.
We are given a small list of countries, each described by three integers: the number of gold, silver, and bronze medals it has won, followed by its name. Our task is to determine which country ranks highest under the standard Olympic ranking rules.
Vertices are binary strings $a{2t-1}ldots a1a0$ with exactly $t$ ones. A move consists of choosing $j in {1,ldots,2t-1}$ and swapping $a0 leftrightarrow aj$. Each move preserves the condition $sum{i=0}^{2t-1} ai = t$, hence maps $(t,t)$-combinations to $(t,t)$-combinations.
I’m missing the actual statement for Codeforces 103379J - Not a Winter Formal, and this problem ID does not have publicly accessible context in the prompt or reliably retrievable structured data in the current environment.
The problem statement for Codeforces 103379I - Santa's Last Journey is missing from your prompt (the “Problem Statement”, “Input”, and “Output” sections are empty).
I don’t have the actual problem statement for Codeforces 103379H - Label Cropping, and the input/output sections in your prompt are empty.
We are given a sequence of locations in a 2D plane, starting from the origin. Santa’s sled does not choose directions freely anymore. Instead, it repeatedly executes a fixed movement pattern given by a string consisting of the four cardinal directions.
I can write the full editorial, but I’m missing the most important part: the actual statement of Codeforces 103379F - Present Drops.
We are missing the actual statement of Codeforces 103379C - Sled Tracks in the prompt you provided. Without the problem definition, any attempt to write a correct editorial would be pure guesswork, and for this particular problem (a graph-style CF task), that would almost…
I can’t write a correct editorial yet because the actual problem statement for Codeforces 103379D - Lazy Santa is missing from your prompt.
Vertices are binary strings $a{2t-1}ldots a1a0$ with exactly $t$ ones. A move consists of choosing $j in {1,ldots,2t-1}$ and swapping $a0 leftrightarrow aj$. Each move preserves the condition $sum{i=0}^{2t-1} ai = t$, hence maps $(t,t)$-combinations to $(t,t)$-combinations.
I don’t have the actual statement for Codeforces 103380H - Label Cropping in your prompt, so there’s no way to correctly reconstruct the problem, constraints, or intended solution path.
The problem statement is missing from your prompt, so I don’t have the actual rules, input format, or what the sled is supposed to compute. Without that, any “full editorial” would just be guesswork, and for a Codeforces writeup that would be unreliable.
The problem statement section is empty in your prompt, so I don’t actually know what “Codeforces 103380F - Present Drops” is asking for.
We are given a weighted undirected graph whose vertices represent locations in Santa’s world. One special vertex is the North Pole, labeled as node 0, and there are several other special vertices that correspond to houses.
I’m missing the actual problem statement for “103380E - Grandest Wreath”. Right now I only have the template and metadata, but no description of what the input represents or what needs to be computed.
I’m missing the actual problem statement for Codeforces 103380C - Sled Tracks in your prompt. Right now there’s no description of what the input represents, what needs to be computed, or even the constraints, so I can’t safely write a correct editorial without guessing.
I’m missing the actual problem statement for Codeforces 103380A - Sad Santa, so I can’t safely reconstruct the correct model or derive the solution without risking inventing details.
Vertices are binary strings $a{2t-1}ldots a1a0$ with exactly $t$ ones. A move consists of choosing $j in {1,ldots,2t-1}$ and swapping $a0 leftrightarrow aj$. Each move preserves the condition $sum{i=0}^{2t-1} ai = t$, hence maps $(t,t)$-combinations to $(t,t)$-combinations.
We are working with an interactive simulation on an $N times N$ grid that represents a Mars surface. Each cell in this grid is either safe or contains a hidden obstacle, and the goal is to reconstruct the entire obstacle map using a rover that can move and query its surroundings.
I can’t reliably write a correct editorial yet because the actual problem statement is missing. Right now I only see the title “Древнее имя” and no definition of what the input represents, what transformations or queries are involved, or what needs to be computed.
I can’t complete a correct editorial yet because the problem statement for Codeforces 1033823 - “Игра” is not provided in your prompt, and it is not available in a reliable, directly referenced form in the input you gave.
The problem statement for “Codeforces 1033821 - Путешествие поездом” is not included in your message, so I don’t have the actual rules, input format, or task definition needed to write a correct editorial.
Vertices are binary strings $a{2t-1}ldots a1a0$ with exactly $t$ ones. A move consists of choosing $j in {1,ldots,2t-1}$ and swapping $a0 leftrightarrow aj$. Each move preserves the condition $sum{i=0}^{2t-1} ai = t$, hence maps $(t,t)$-combinations to $(t,t)$-combinations.
I can write the full editorial in exactly that format, but I’m missing the actual problem statement for Codeforces 1033835 - “Долгое вычитание, Карл!”.
I can’t safely write a correct editorial yet because the problem statement for Codeforces 1033834 - “Любовь и двери” is not available from the standard CF archive under that ID, and it does not correspond cleanly to any known Codeforces problem format or index.
We are given a scenario involving two collectors who each own an infinite multiset of “bone segments”: for every positive integer length, each collector has exactly two identical segments of that length.
I don’t have the actual problem statement for Codeforces 1033832 (“Потерявшееся число”) in your message, so I can’t reliably reconstruct or solve it without guessing.
Vertices are binary strings $a{2t-1}ldots a1a0$ with exactly $t$ ones. A move consists of choosing $j in {1,ldots,2t-1}$ and swapping $a0 leftrightarrow aj$. Each move preserves the condition $sum{i=0}^{2t-1} ai = t$, hence maps $(t,t)$-combinations to $(t,t)$-combinations.
I’m missing the actual problem content for Codeforces 1033845 - Финансовая реформа. Right now the statement, input format, and output format sections are empty, so there’s no way to derive the algorithm, constraints, or edge cases.
I’m missing the actual problem statement for Codeforces 1033844 - Путешествие по джунглям, so I can’t reliably reconstruct the solution or write a correct editorial.
The problem statement section is empty, so there is no way to reconstruct the task, constraints, or required output.
I’m missing the actual problem statement for Codeforces 1033842 - “Ну все, я попрыгал!”, so I can’t safely reconstruct the logic or write a correct editorial.
Vertices are binary strings $a{2t-1}ldots a1a0$ with exactly $t$ ones. A move consists of choosing $j in {1,ldots,2t-1}$ and swapping $a0 leftrightarrow aj$. Each move preserves the condition $sum{i=0}^{2t-1} ai = t$, hence maps $(t,t)$-combinations to $(t,t)$-combinations.
The problem statement didn’t come through (it’s blank in your prompt), and for a Codeforces editorial that makes it impossible to write a correct solution without guessing.
The statement for Codeforces 1033854 - “Обучение шахматам” is missing from your prompt, so I can’t safely reconstruct the problem or produce a correct editorial.
The problem statement for “Codeforces 1033851 - Отпуск” is missing from your message, so I don’t have enough information to write a correct editorial.
I can’t write a correct editorial for this yet because the actual problem content is missing. Right now I only see the title “Конструктор”, but there is no statement, input/output format, or constraints.
Let $\mathcal{A}$ be a family of $s$-combinations and $\mathcal{B}$ a family of $t$-combinations, both subsets of $U={0,1,\dots,n-1}$ with $n\ge s+t$.
Think of the string as defining a walk starting at index 0. Every B behaves like a forced edge to i+1. Every A behaves like a node with two outgoing possibilities, one to i+1 and one to i+2.
Let $alpha = a1 a2 dots an$ be a permutation of ${1,dots,n}$. Let $pi$ denote the inverse permutation, so $pi(ai)=i$. The inversion table from Section 7.2.1.2 is defined by $cj = {, i : pi(i) pi(j), i < j }, qquad 1 le j le n,$ so $0 le cj < j$.
The task is essentially about processing a stream of text tokens and extracting a very specific character statistic from them. Instead of performing any structural parsing or transformation, we read all input strings and focus only on occurrences of the hyphen character -.
We are working with a weighted tree and we want to select a set of edges such that no two chosen edges share an endpoint. This is the classical edge independent set condition, which is equivalent to a matching on a tree. Each chosen edge contributes its weight to the total score.
The task is essentially a step by step simulation problem involving a kart that follows a sequence of driving instructions. You are given an initial state of the kart and then a list of commands.
The problem statement for “Codeforces 103389G - 3G网络” is missing from your prompt, so there’s no way to reliably reconstruct the task or produce a correct editorial.
Let vertices be all binary strings $a{2t-1}dots a1a0$ with exactly $t$ zeros and $t$ ones. A move consists of choosing some index $j in {1,dots,2t-1}$ and swapping $a0$ with $aj$, producing a new string that still has $t$ zeros and $t$ ones.
We are given a rectangular grid of characters, and the task is to determine how much the grid can be compressed by periodic repetition in both dimensions.
We are given two integer sequences that describe a kind of composition process. One sequence can be thought of as a base transformation, and the other is the result after applying that transformation multiple times.
We are given a sequence of integers, where each position can be interpreted as a node in a line, and the value at each position represents a weight or height associated with that node.
We are given a fixed string s of length n, and multiple queries. Each query gives a segment [l, r] inside s. For each segment, we are asked to construct a new string t that is as short as possible while still failing to appear as a subsequence of s[l..r].
We are given a bus route with a fixed ordered list of stops. A passenger reports a sequence of stops they observed while riding the bus, but there is a complication: the bus might be traveling in the forward direction of the route or in the reverse direction.
Let $\mathcal{A}$ be a family of $s$-combinations and $\mathcal{B}$ a family of $t$-combinations, both subsets of $U={0,1,\dots,n-1}$ with $n\ge s+t$.
Let $a{s+t-1}dots a1a0$ be the binary representation of an $(s,t)$-combination, so each $ai in {0,1}$ and $sum ai = t$. A rotation of a prefix of length $j+1$ is the transformation $$aj a{j-1}dots a0 ;leftarrow; a{j-1}dots a0 aj,$$ with all other digits unchanged.
We are given two integers and asked to compute their product under a very large modulus, where the modulus is a full 64-bit value.
We repeatedly generate triples (x, y, m) using a deterministic XOR-shift RNG. Each triple represents a modular multiplication request where both operands and modulus are close to the limits of 63-bit integers.
You've hit your limit. Please try again later.
Let $a{s+t-1}dots a1a0$ be the binary representation of an $(s,t)$-combination, so each $ai in {0,1}$ and $sum ai = t$. A rotation of a prefix of length $j+1$ is the transformation $$aj a{j-1}dots a0 ;leftarrow; a{j-1}dots a0 aj,$$ with all other digits unchanged.
I can’t write a correct editorial for Codeforces 103401M - Debug it! because the actual problem statement (input/output rules and constraints) is missing from your prompt.
I can’t reliably write a correct editorial here because the actual problem statement for “Codeforces 103401L - Carrot Fantasy” is missing from your prompt.
We are given a sequence of points on a 2D grid. A robot starts at the origin and must visit these points in order, where “visiting” means the robot must physically reach each coordinate in sequence.
I can write the full editorial in the exact style you want, but the problem statement for Codeforces 103401J - League schedule is not included in your prompt. Right now there is no description of: - what entities are involved (teams, rounds, constraints, etc.
Let $a{s+t-1}dots a1a0$ be the binary representation of an $(s,t)$-combination, so each $ai in {0,1}$ and $sum ai = t$. A rotation of a prefix of length $j+1$ is the transformation $$aj a{j-1}dots a0 ;leftarrow; a{j-1}dots a0 aj,$$ with all other digits unchanged.
I can write a full editorial in the exact format you requested, but I’m missing one essential piece: the actual problem statement for Codeforces 103401H - Observe.
The problem statement for Codeforces 103401G - Environmental friendly is missing from your prompt, so I can’t reconstruct a correct editorial without risking inventing details.
I can write the full editorial in the exact format you want, but I’m missing the actual problem statement for Codeforces 103401F - lzd is a scout.
I can’t produce a correct editorial yet because the statement that was retrieved for 103401E - Power tower is incomplete and inconsistent across sources.
The editorial can’t be written correctly yet because the actual problem statement for Codeforces 103401D - Hard Nim is missing.