Soy Cup #1: Firefly

13 problems from Soy Cup #1: Firefly (contest 105920), difficulty -. 13/13 solutions verified against sample I/O.

13 items

Soy Cup #1: Firefly

Special | 13 problems | 13/13 verified | Difficulty - | 12m 54s

# Problem Rating Tags Accepted Time ✓
A Clan Battle 48s ✓
B Nabi Puzzle 45s ✓
C Dominance 50s ✓
D Greedy Counting 48s ✓
E Ever Forever 52s ✓
F Pull 47s ✓
G DSU 53s ✓
H Simple XOR Problem 55s ✓
I Ciallo 1m 34s ✓
J Bridge III 1m 11s ✓
K Painting the Tree 1m 1s ✓
L Fyreflies 50s ✓
M Magical Book 1m 40s ✓
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CF 105920M - Magical Book

We are given a string consisting only of opening and closing parentheses. For every query, we look at a fixed interval inside this string and count how many different substrings fully inside that interval form a correct bracket sequence.
codeforces competitive-programming Jun 22, 2026
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CF 105920J - Bridge III

The input describes a sequence of actions in a simplified bridge auction. Four players act in a fixed cyclic order, and each action is either a bid (an auction like “2C” or “1S”), a pass, a double, or a redouble. The rules govern how these actions can legally appear.
codeforces competitive-programming Jun 22, 2026
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CF 105920E - Ever Forever

We maintain a dynamic set of strings that changes over time. After every update, we must compute how many ordered pairs of distinct words currently in the set have the property that one word is a suffix of the other. In other words, at each moment we have a collection of strings.
codeforces competitive-programming Jun 22, 2026
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CF 105920A - Clan Battle

We are given a sequence of bosses that Kyouka attempts to defeat in a fixed order. Each boss type can appear multiple times, and these appearances are not independent: the availability of a boss in later “rounds” depends on what has already been defeated earlier in the…
codeforces competitive-programming Jun 22, 2026
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CF 105920K - Painting the Tree

We are given a tree where each vertex starts with a color. Then we process a sequence of repaint operations, each of which overwrites colors on a specific set of vertices. The goal is to determine the final color of every vertex after all operations are applied in order.
codeforces competitive-programming Jun 21, 2026
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CF 105920L - Fyreflies

We are given several hidden positions on a number line from 1 to 100000. These positions represent locations of firefly groups. We do not know the positions, and multiple groups may exist at different points.
codeforces competitive-programming Jun 21, 2026
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CF 105920H - Simple XOR Problem

We are asked to evaluate a range expression over integers from $l$ to $r$. For each number $x$ in this interval, we take the bitwise XOR of $x$ with a fixed integer $y$, interpret the result as a value, and then aggregate those results over the entire range.
codeforces competitive-programming Jun 21, 2026
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CF 105920G - DSU

We are given a single array f of size n. This array is claimed to be the final state of a Disjoint Set Union structure that started from f[i] = i for every element and then had at most n calls to a merge(u, v) operation. The DSU implementation is slightly asymmetric.
codeforces competitive-programming Jun 21, 2026
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CF 105920D - Greedy Counting

We are given an array, and instead of computing a classical longest increasing subsequence, we apply a very specific greedy procedure to every contiguous subarray and sum the results.
codeforces competitive-programming Jun 21, 2026
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CF 105920B - Nabi Puzzle

We are asked to construct an integer array of length n, assigning a value to each position in a line of Nabis. The assignment must satisfy two sliding window constraints simultaneously. For every contiguous segment of length p, the sum of its elements must be strictly positive.
codeforces competitive-programming Jun 21, 2026
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CF 105920I - Ciallo

We are given two strings, and we are allowed to build new strings by taking a prefix of the first string and concatenating it with a suffix of the second string.
codeforces competitive-programming Jun 21, 2026
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CF 105920F - Pull

We are modeling a repeating random process where each “cycle” consists of drawing until we obtain a rare event, then resetting. Each draw has a probability of producing a 6-star result, but this probability is not fixed.
codeforces competitive-programming Jun 21, 2026
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CF 105920C - Dominance

We are given several independent matrices. Each matrix contains a permutation of values, meaning every number from 1 up to n·m appears exactly once.
codeforces competitive-programming Jun 21, 2026