Codeforces Round 931 (Div. 2)

Solutions for Codeforces Round 931 (Div. 2) (contest 1934). 2/6 problems verified against sample I/O. Difficulty range: 800-3000.

6 items

Codeforces Round 931 (Div. 2)

Type: Div. 2 | Problems: 6 | Verified: 2/6 | Rating range: 800-3000 | Time: 11m 46s

Problem Name Rating Tags Solve Time Verified
A Too Min Too Max 800 greedy, math 2m 17s ✗
B Yet Another Coin Problem 1200 brute-force, dp, greedy 1m 20s ✓
C Find a Mine 1700 binary-search, constructive-algorithms, geometry 2m 6s ✗
D1 XOR Break --- Solo Version 2100 bitmasks, constructive-algorithms, greedy 2m 17s ✗
D2 XOR Break --- Game Version 2400 bitmasks, games, greedy 1m 52s ✗
E Weird LCM Operations 3000 brute-force, constructive-algorithms, number-theory 1m 54s ✓
Practice › Codeforces Solutions › Codeforces Round 931 (Div. 2) ›

Practice › Codeforces Solutions › Codeforces Round 931 (Div. 2) ›

CF 1934E - Weird LCM Operations

We start with an array that initially contains the identity permutation, so position $i$ holds value $i$. The only allowed operation picks three distinct positions and replaces the values at those positions with pairwise least common multiples of the other two values.
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CF 1934D2 - XOR Break --- Game Version

We are given a starting number and two players who alternately “decompose” it. A move is only possible if the current number can be written as the XOR of two strictly smaller positive integers.
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CF 1934D1 - XOR Break --- Solo Version

We start with a single integer state, initially equal to n. The only way to change it is through a constrained “break” operation that uses a secondary value y.
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CF 1934C - Find a Mine

We are given a very large grid with n rows and m columns, where n and m can each be up to 10^8. In this grid, exactly two cells contain mines at distinct coordinates.
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CF 1934B - Yet Another Coin Problem

We are given a fixed set of coin denominations: 1, 3, 6, 10, and 15. For each query, we must construct an exact total value n using any number of these coins, with the goal of minimizing how many coins are used.
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