Deltix Round, Autumn 2021 (open for everyone, rated, Div. 1 + Div. 2)
Solutions for Deltix Round, Autumn 2021 (open for everyone, rated, Div. 1 + Div. 2) (contest 1609). 2/8 problems verified against sample I/O. Difficulty range: 900-3500.
Deltix Round, Autumn 2021 (open for everyone, rated, Div. 1 + Div. 2)
Type: Div. 1+2 | Problems: 8 | Verified: 2/8 | Rating range: 900-3500 | Time: 21m 10s
| Problem | Name | Rating | Tags | Solve Time | Verified |
|---|---|---|---|---|---|
| A | Divide and Multiply | 900 | greedy, implementation, math | 1m 28s | ✓ |
| B | William the Vigilant | 1100 | implementation, strings | 9m 11s | ✗ |
| C | Complex Market Analysis | 1400 | binary-search, dp, implementation | 1m 36s | ✓ |
| D | Social Network | 1600 | dsu, graphs, greedy | 1m 52s | ✗ |
| E | William The Oblivious | 2400 | bitmasks, data-structures, dp | 1m 55s | ✗ |
| F | Interesting Sections | 2800 | data-structures, divide-and-conquer, meet-in-the-middle | 1m 40s | ✗ |
| G | A Stroll Around the Matrix | 3000 | data-structures, greedy, math | 1m 56s | ✗ |
| H | Pushing Robots | 3500 | - | 1m 32s | ✗ |
CF 1609B - William the Vigilant
The mismatch you are seeing (“correct count but invalid orientation”, sometimes even extra vertices counted) is a strong signal that the previous construction is not just buggy, but conceptually wrong.
CF 1609H - Pushing Robots
We are asked to simulate the movement of robots on a number line. Each robot occupies a unit segment and follows a cyclic program of instructions that can push it left, right, or leave it stationary.
CF 1609G - A Stroll Around the Matrix
We are working with two integer arrays, one of size $n$ and one of size $m$. Together they define an $n times m$ grid where each cell value is the sum of a row contribution and a column contribution.
CF 1609F - Interesting Sections
We are given a long array of non-negative integers. The task is to count how many contiguous subarrays have a specific property that depends on two extreme values inside the subarray: its minimum and its maximum.
CF 1609E - William The Oblivious
We are working with a mutable string consisting only of the characters a, b, and c. After each update, we must answer a structural question about the string: how many positions must be changed so that the string no longer contains abc as a subsequence.
CF 1609D - Social Network
We are given a group of people who initially have no relationships at all. Over time, we are shown a sequence of pairs, and each pair represents a constraint that must eventually be satisfied: the two people in the pair must end up connected, meaning there exists a chain of…
CF 1609C - Complex Market Analysis
We are given an array of integers and a step size e. For each starting index i, we can form a subsequence by taking every e-th element: a[i], a[i+e], a[i+2e], ... up to the point where the index does not exceed the array bounds.
CF 1609A - Divide and Multiply
We are given several independent test cases. Each test case consists of a small array of integers, and we are allowed to repeatedly redistribute factors of two between elements.