Codeforces Round 829 (Div. 1)

Solutions for Codeforces Round 829 (Div. 1) (contest 1753). 2/7 problems verified against sample I/O. Difficulty range: 1300-3500.

7 items

Codeforces Round 829 (Div. 1)

Type: Div. 1 | Problems: 7 | Verified: 2/7 | Rating range: 1300-3500 | Time: 19m 17s

Problem Name Rating Tags Solve Time Verified
A1 Make Nonzero Sum (easy version) 1300 constructive-algorithms, dp, greedy 2m 58s ✗
A2 Make Nonzero Sum (hard version) 1500 constructive-algorithms, dp, greedy 1m 14s ✗
B Factorial Divisibility 1600 math, number-theory 4m 40s ✓
C Wish I Knew How to Sort 2000 dp, math, probabilities 2m 20s ✗
D The Beach 2400 constructive-algorithms, dfs-and-similar, graphs 2m 19s ✗
E N Machines 3300 binary-search, brute-force, greedy 2m ✗
F Minecraft Series 3500 brute-force, two-pointers 3m 46s ✓
Practice › Codeforces Solutions › Codeforces Round 829 (Div. 1) ›

CF 1753F - Minecraft Series

The reported failure is not actually an algorithmic error. The traceback shows: This means the test harness tried to execute: but the submitted code did not define a function named solve. The program failed before reading the input or constructing any permutation.
codeforces competitive-programming brute-force two-pointers Jun 9, 2026
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CF 1753E - N Machines

We are given a sequence of machines applied one after another to a single value starting from 1. Each machine either adds a fixed value or multiplies by a fixed value. The final result after running through the entire chain depends entirely on the order of machines.
codeforces competitive-programming binary-search brute-force greedy Jun 9, 2026
Practice › Codeforces Solutions › Codeforces Round 829 (Div. 1) ›

CF 1753D - The Beach

We are given a grid representing a beach where each cell is either empty sand, an obstacle, or part of a sunbed. Each sunbed occupies exactly two adjacent cells and is encoded using directional halves, so each pair of cells forms a rigid domino.
codeforces competitive-programming constructive-algorithms dfs-and-similar graphs shortest-paths Jun 9, 2026
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CF 1753B - Factorial Divisibility

We are asked to determine whether the sum of factorials of an array of integers is divisible by another factorial. More concretely, we are given an array [a1, a2, ..., an] and a number x. We want to know if (a1! + a2! + ... + an!) is divisible by x!.
codeforces competitive-programming math number-theory Jun 9, 2026
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CF 1753C - Wish I Knew How to Sort

We are given a binary array, meaning every element is either 0 or 1. The array evolves through repeated random operations: at each step we pick a uniformly random pair of indices $(i, j)$ with $i < j$.
codeforces competitive-programming dp math probabilities Jun 9, 2026
Practice › Codeforces Solutions › Codeforces Round 829 (Div. 1) ›

CF 1753A1 - Make Nonzero Sum (easy version)

We are given an array consisting solely of 1s and -1s. Our task is to split this array into consecutive segments where each segment has an alternating sum defined as the first element minus the second plus the third minus the fourth, and so on.
codeforces competitive-programming constructive-algorithms dp greedy Jun 9, 2026
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CF 1753A2 - Make Nonzero Sum (hard version)

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codeforces competitive-programming constructive-algorithms dp greedy Jun 9, 2026