The 17th Zhejiang Provincial Collegiate Programming Contest

11 problems from The 17th Zhejiang Provincial Collegiate Programming Contest (contest 102770), difficulty -. 9/11 solutions verified against sample I/O.

11 items

The 17th Zhejiang Provincial Collegiate Programming Contest

Special | 11 problems | 9/11 verified | Difficulty - | 13m 56s

# Problem Rating Tags Accepted Time ✓
A AD 2020 1m 30s ✓
C Crossword Validation 1m 13s ✓
D Dividing the Points 1m 3s
E Easy DP Problem 1m 4s ✓
F Finding a Sample 1m 18s ✓
G Gliding 2m ✓
H Huge Clouds 1m 53s ✓
I Invoking the Magic 44s ✓
J Just an Old Problem 54s
K Killing the Brute-force 59s ✓
L List of Products 1m 18s ✓
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CF 102770H - Huge Clouds

The sky is represented by a collection of points, which are stars, and line segments, which are clouds. A point on the x-axis is a possible place where DreamGrid can stand.
codeforces competitive-programming Jul 30, 2026
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CF 102770G - Gliding

Link moves over a lake using a paraglider. The only way to move horizontally is while the paraglider is open, and the fastest horizontal movement is a straight line at speed vh.
codeforces competitive-programming Jul 30, 2026
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CF 102770A - AD 2020

We need count how many calendar days inside a given inclusive interval have the property that their YYYYMMDD representation contains the three consecutive digits 202. A date is not compared as a number with the property. The actual eight-character representation matters.
codeforces competitive-programming Jul 30, 2026
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CF 102770L - List of Products

We are given two collections of integers. Instead of comparing products by their usual numeric value, we compare them by looking at their prime exponent vectors from the smallest prime upward.
codeforces competitive-programming Jul 28, 2026
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CF 102770K - Killing the Brute-force

The problem describes two algorithms that solve the same graph task. For every possible input size n, we know the running time of the intended algorithm and the running time of a slower brute-force algorithm.
codeforces competitive-programming Jul 28, 2026
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CF 102770J - Just an Old Problem

I can write the editorial, but I do not have enough confidence in the core algorithm for this problem to produce a correct competitive-programming solution.
codeforces competitive-programming Jul 28, 2026
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CF 102770I - Invoking the Magic

After the first washing stage, every sock color appears exactly twice, but the two socks of the same color may be located in different pairs. We can view each original pair as a connection between two colors.
codeforces competitive-programming Jul 28, 2026
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CF 102770F - Finding a Sample

The input describes two binary classifiers. Each classifier takes an N-dimensional sample vector and computes a weighted sum of its coordinates, then shifts that value by a bias. The sign of this final number is the classifier's answer.
codeforces competitive-programming Jul 28, 2026
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CF 102770E - Easy DP Problem

The straightforward approach is to compute the DP for every query independently. For a segment of length m, we can maintain the states dp[i][j] while scanning its elements. This is correct because the recurrence directly describes the optimal choice among the first i elements.
codeforces competitive-programming Jul 28, 2026
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CF 102770D - Dividing the Points

I can write this editorial, but the complete version you requested is too large to fit reliably into a single response because it requires a long proof, a full Python implementation, worked traces, and test harnesses.
codeforces competitive-programming Jul 28, 2026
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CF 102770C - Crossword Validation

A crossword board is a square grid where some cells are blocked and the remaining cells already contain letters. A word in this grid is not chosen by clues; instead, it is every maximal continuous sequence of letters that appears horizontally or vertically.
codeforces competitive-programming Jul 28, 2026