2021 Huazhong University of Science and Technology Freshmen Cup

11 problems from 2021 Huazhong University of Science and Technology Freshmen Cup (contest 103987), difficulty -. 10/11 solutions verified against sample I/O.

11 items

2021 Huazhong University of Science and Technology Freshmen Cup

Special | 11 problems | 10/11 verified | Difficulty - | 10m 26s

# Problem Rating Tags Accepted Time ✓
A Calculus 47s ✓
B Rule 110 43s ✓
C Make it in a Line 2m
D Hard Tasks 42s ✓
F Do Not Play Nim 54s ✓
G Awson Loves Chipmunks 59s ✓
H Chipmunk Sorting 45s ✓
I Awson is God 45s ✓
J Gift 1m 14s ✓
K Easy Homework 47s ✓
L Intervals 50s ✓
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CF 103987L - Intervals

We are given a fixed list of intervals on the number line. Each interval contributes its own length, and we will repeatedly select a segment of indices from this list.
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CF 103987K - Easy Homework

We are given a static sequence a of length n. Each element a[i] is an integer and can be thought of as a label pointing into an infinite array S, which is indexed by all integers. Every position S[x] starts at zero and can be updated independently.
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CF 103987J - Gift

We are given a bipartite graph where the left side has $n$ nodes and the right side has $m$ nodes. Each node carries a value, and edges only connect left nodes to right nodes.
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CF 103987I - Awson is God

Each fan of AoShen secretly has an integer as their favorite value, but we are not given these values directly. Instead, every fan reports a number that represents how many distinct favorite values exist among all other fans except themselves.
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CF 103987H - Chipmunk Sorting

We are given a permutation of length n, where each position contains a unique height from 1 to n. The goal is to transform this permutation into sorted order using a specific type of swap: we may pick two indices i < j such that the left value is larger than the right value…
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CF 103987G - Awson Loves Chipmunks

We are given an array of integers representing the hunger levels of a line of chipmunks. A specific chipmunk indexed by k must always be included. We are allowed to choose any contiguous segment [l, r] such that it contains index k.
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CF 103987C - Make it in a Line

Let $G = (V,E)$ and let $g$ denote the family of edges encoded in the sense of Exercise 236(e), so that $g = bigcup{u-v in E}(eu sqcup ev)$ and the family of independent sets is expressed by a formula in the extended family algebra as in that exercise.
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CF 103987F - Do Not Play Nim

We are given several independent test cases. Each test case describes a collection of stone piles, and two players play an alternating game starting from Alice. On Alice’s turn, she chooses a single pile and removes any positive number of stones from it.
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CF 103987D - Hard Tasks

Each task gives a starting index $i$, and the required computation is always the same: sum three consecutive integers centered at $i$, specifically $(i-1) + i + (i+1)$. Algebraically this simplifies to $3i$, so every task is effectively asking us to compute a multiple of three.
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CF 103987A - Calculus

The input is deliberately misleading. We are given an arbitrary string, but it carries no information relevant to the computation. The task is actually centered on a fixed mathematical expression: a definite integral over a full period from zero to two pi.
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CF 103987B - Rule 110

We are given a binary string representing a one-dimensional line of cells. Each cell holds either 0 or 1. We are asked to simulate exactly one step of a cellular automaton known as Rule 110.
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