CCF CAT NAEC 2025 (Final)

10 problems from CCF CAT NAEC 2025 (Final) (contest 106026), difficulty -. 10/10 solutions verified against sample I/O.

10 items

CCF CAT NAEC 2025 (Final)

Special | 10 problems | 10/10 verified | Difficulty - | 10m 2s

#	Problem	Time	✓
A	\u5907\u7528\u8d26\u53f7	52s	✓
B	\u8fdb\u5236\u53d8\u6362	51s	✓
C	\u6216\u975e	1m 13s	✓
D	Fever Dash	1m 6s	✓
E	\u7b80\u5355\u7684\u6570\u636e\u7ed3\u6784\u9898	1m 1s	✓
F	\u4e71\u5e8f\u6cd5\u6756	1m	✓
G	Good Number	1m	✓
H	\u5feb\u901f\u6392\u5217\u7f6e\u6362	1m 3s	✓
I	Emotional Flutter	1m 5s	✓
J	Eternal Feather II	51s	✓

Practice › Codeforces Solutions › CCF CAT NAEC 2025 (Final) ›

CF 106026I - Emotional Flutter

We are given three fixed convex polygons in the plane. Each polygon represents a region where one of three point masses must be placed.

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CF 106026D - Fever Dash

We are given a rhythm game where notes arrive at specific times. Each note contributes a base score and also contributes energy toward a “Fever gauge”. Once this gauge reaches a threshold, we are allowed to activate a Fever mode.

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CF 106026H - 快速排列置换

We are given a permutation $a$ of size $n$, so it is a bijection from positions $1 ldots n$ to values $1 ldots n$.

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CF 106026G - Good Number

We are given an integer range $[L, R]$, and for every integer $x$ in this range we look at its decimal representation and count how many times each digit $0$ to $9$ appears. Let that count for digit $i$ be $F(x, i)$.

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CF 106026C - 或非

We are given a complete graph on vertices labeled from 0 to n-1. Every pair of vertices is connected, and the weight of an edge is not a simple arithmetic value but a bitwise construction based on the labels of its endpoints.

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CF 106026J - Eternal Feather II

We are given a very long string length $n$, but we are not asked to construct strings explicitly. Instead, we work over strings formed from the fixed alphabet ${y, u, k, o}$, and we want to count how many such strings of length $n$ are “valid”.

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CF 106026E - 简单的数据结构题

We are maintaining a long array where every element is always a 4-bit value, so each value lies in the range from 0 to 15. The array changes over time through range updates, and occasionally we are asked to compute a summary statistic over a range.

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CF 106026F - 乱序法杖

Each sheep starts with an integer health value. We are given a multiset of operations that will be applied in a uniformly random order: some number of “healing” spells and some number of “damage” spells.

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CF 106026A - 备用账号

We are given a list of usernames, and we want to count how many unordered pairs of usernames can be considered “account variants” of each other.

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CF 106026B - 进制变换

We are given two integers, and we are allowed to transform a current value into a new value using a very specific operation.