Codeforces Round 1061 (Div. 2)

7 problems from Codeforces Round 1061 (Div. 2) (contest 2156), difficulty 800-3000. 3/7 solutions verified against sample I/O.

7 items

Codeforces Round 1061 (Div. 2)

Div. 2 | 7 problems | 3/7 verified | Difficulty 800-3000 | 12m 24s

#	Problem	Rating	Tags	Accepted	Time	✓
A	Pizza Time	800	brute-force, constructive-algorithms, greedy	26,853	1m 8s	✓
B	Strange Machine	1000	binary-search, brute-force, greedy	20,750	1m 19s	✓
C	Maximum GCD on Whiteboard	1400	greedy, math, number-theory	12,270	1m 37s
D	Find the Last Number	1900	binary-search, bitmasks, constructive-algorithms	5,369	1m 43s
E	Best Time to Buy and Sell Stock	2500	binary-search, brute-force, data-structures	959	1m 49s
F1	Strange Operation (Easy Version)	2200	brute-force, data-structures, greedy	1,617	3m 16s	✓
F2	Strange Operation (Hard Version)	3000	data-structures, greedy, trees	243	1m 32s

Practice › Codeforces Solutions › Codeforces Round 1061 (Div. 2) ›

CF 2156F1 - Strange Operation (Easy Version)

We are given a permutation of integers from 1 to $n$. The allowed operation selects three indices $i < j < k$ such that the value at $i$ is exactly one more than the maximum of $pj$ and $pk$ and exactly two more than the minimum of $pj$ and $pk$.

Practice › Codeforces Solutions › Codeforces Round 1061 (Div. 2) ›

CF 2156F2 - Strange Operation (Hard Version)

We start with a permutation of length $n$, meaning every integer from $1$ to $n$ appears exactly once in some order.

Practice › Codeforces Solutions › Codeforces Round 1061 (Div. 2) ›

CF 2156E - Best Time to Buy and Sell Stock

We are given a list of numbers and two players who interact with it in a turn-based process. The key twist is that the final outcome is not chosen directly, but emerges from a game where one player removes elements from consideration and the other permanently freezes elements…

Practice › Codeforces Solutions › Codeforces Round 1061 (Div. 2) ›

CF 2156D - Find the Last Number

We are given a hidden permutation of integers from 1 to $n$, but we only have direct access to the first $n-1$ elements through an interactive query.

Practice › Codeforces Solutions › Codeforces Round 1061 (Div. 2) ›

CF 2156C - Maximum GCD on Whiteboard

We are given a collection of integers on a whiteboard and two operations to modify it. The first operation, Erase, allows us to remove up to $k$ numbers.

Practice › Codeforces Solutions › Codeforces Round 1061 (Div. 2) ›

CF 2156B - Strange Machine

We have a circular arrangement of up to 20 machines, each of which either decreases an integer by one (type A) or halves it and floors the result (type B).

Practice › Codeforces Solutions › Codeforces Round 1061 (Div. 2) ›

CF 2156A - Pizza Time

We are repeatedly shrinking a pile of pizza slices using a very specific rule until only a tiny remainder is left. The process is deterministic in structure but flexible in how we split the pile, and our only freedom is how we choose that split each day.