OCPC Potluck Contest 1 (The 3rd Universal Cup. Stage 6: Osijek)

12 problems from OCPC Potluck Contest 1 (The 3rd Universal Cup. Stage 6: Osijek) (contest 105388), difficulty -. 12/12 solutions verified against sample I/O.

12 items

OCPC Potluck Contest 1 (The 3rd Universal Cup. Stage 6: Osijek)

Special | 12 problems | 12/12 verified | Difficulty - | 13m 6s

# Problem Rating Tags Accepted Time ✓
A Coprime Array 54s ✓
B Square Locator 1m 39s ✓
C -is-this-bitset- 1m 6s ✓
D Cycle Game 1m 7s ✓
E Sum of Squares 1m 3s ✓
F Alternating Cycle 1m 1s ✓
G Touching Grass 1m 5s ✓
H Game Design 1m 10s ✓
I Geometry Hacking 1m 13s ✓
J Non-Interactive Nim 1m 1s ✓
K String and Nails 50s ✓
L All-You-Can-Eat 57s ✓
Practice › Codeforces Solutions › OCPC Potluck Contest 1 (The 3rd Universal Cup. Stage 6: Osijek) ›

CF 105388B - Square Locator

We are asked to reconstruct a geometric object from partial metric information. There is a square in the plane whose vertices lie on integer coordinates.
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CF 105388L - All-You-Can-Eat

We are interacting with a sequence of meals that arrive one by one, each carrying a non-negative calorie value. At any moment we may either ignore a meal or take it, but taking it adds it permanently to a current “plate set” whose total calorie sum must never exceed 1000.
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CF 105388H - Game Design

We are asked to count how many ways we can wire a system of one-to-one connections between entry portals and exit portals spread across levels 1 to n.
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CF 105388K - String and Nails

We are given a set of points in the plane, called nails. At any moment we imagine wrapping a tight rubber band around all remaining nails, so the band forms the convex hull of the current set.
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CF 105388D - Cycle Game

We are given a rectangular grid of size $n times m$, initially empty. Moves arrive one by one in a fixed order, and each move paints a previously unpainted cell black. After each move, we need to decide whether that move is allowed to be placed or whether it should be skipped.
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CF 105388F - Alternating Cycle

We are given a set of points in the plane, with the guarantee that no three are collinear. From this set, we are allowed to choose a non-empty subset and arrange it in a cyclic order.
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CF 105388J - Non-Interactive Nim

We are given several independent instances of a Nim game. Each instance consists of multiple piles, and a move consists of selecting one pile and removing a positive number of stones from it.
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CF 105388I - Geometry Hacking

We are given a very specific geometric bug to exploit. A point is fixed at the origin, and we are asked to construct simple lattice polygons that truly enclose this point strictly inside them. “Strictly inside” means the origin cannot lie on any edge or vertex.
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CF 105388G - Touching Grass

We are given a set of vertical line segments in the plane, each anchored on the x-axis and extending upward. Concretely, the i-th grass is a segment from $(xi, 0)$ to $(xi, yi)$, and all x-coordinates are distinct.
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CF 105388E - Sum of Squares

We are given a univariate polynomial $A(x)$ and we build a multivariate polynomial $D(x1, dots, xm)$ by taking two ingredients. The first is a copy of $A$ applied independently to each variable, so every variable contributes a factor $A(xi)$.
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CF 105388C - -is-this-bitset-

We are given a rooted binary tree with up to 300,000 nodes. Each node carries a weight a[i], and each node also has a target value b[i]. For every node i, we look only at the nodes on the path from the root to i, including i itself.
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CF 105388A - Coprime Array

We are given two integers, a target sum s and a constraint value x. The task is to construct an array whose elements add up exactly to s, while every element in the array must be coprime with x. Coprime here means that each element shares no common prime factor with x.
codeforces competitive-programming Jun 23, 2026