Codeforces Round 1085 (Div. 1 + Div. 2)

11 problems from Codeforces Round 1085 (Div. 1 + Div. 2) (contest 2207), difficulty 800-3300. 0/11 solutions verified against sample I/O.

11 items

Codeforces Round 1085 (Div. 1 + Div. 2)

Div. 1+2 | 11 problems | 0/11 verified | Difficulty 800-3300 | 22m 3s

#	Problem	Rating	Tags	Accepted	Time
A	1-1	800	greedy, strings	13,650	1m 54s
B	One Night At Freddy's	1600	games, greedy, sortings	5,785	1m 48s
C	Where's My Water?	1600	data-structures, divide-and-conquer, dp	5,420	2m 25s
D	Boxed Like a Fish	2200	dfs-and-similar, dp, games	2,106	1m 46s
E1	N-MEX (Constructive Version)	2100	constructive-algorithms, greedy	1,658	2m 20s
E2	N-MEX (Counting Version)	2400	combinatorics, constructive-algorithms, math	858	1m 51s
F	Hanabi	2900	binary-search, data-structures, dp	268	2m 2s
G	Toothless	3300	constructive-algorithms, dfs-and-similar, dsu	154	2m 4s
H1	Bowser's Castle (Easy Version)		binary-search, constructive-algorithms, divide-and-conquer	51	1m 51s
H2	Bowser's Castle (Medium Version)		constructive-algorithms, divide-and-conquer, interactive	39	2m 17s
H3	Bowser's Castle (Hard Version)		constructive-algorithms, divide-and-conquer, interactive	56	1m 45s

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CF 2207H2 - Bowser's Castle (Medium Version)

We are asked to reverse-engineer a hidden function chosen by Bowser. The function takes n integer inputs and is constructed entirely from nested min and max operations, each input appearing exactly once in order from x1 to xn.

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CF 2207H3 - Bowser's Castle (Hard Version)

We are given a black-box function of $n$ variables. The function is not arbitrary: it is built by taking the variables $x1, x2, ldots, xn$ in order and combining them using only min and max, with the restriction that each variable appears exactly once and in that fixed…

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CF 2207G - Toothless

We are given an n × m grid representing sand, initially all white. Some cells are marked as needy () and must be painted black. Other cells are either special (x) or normal (.), and each non-needy cell has a value: special cells are worth b and normal cells are worth a.

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CF 2207H1 - Bowser's Castle (Easy Version)

We are given an unknown function that takes a list of n values and returns a single number. The function is not arbitrary: it is built by combining the inputs using only min and max, and every input variable appears exactly once, in order.

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CF 2207F - Hanabi

The problem gives us a Hanabi-like card game where Zuko holds all cards in a single row, one for each combination of rank and color. Iroh can see the cards, but Zuko cannot.

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CF 2207E2 - N-MEX (Counting Version)

We are asked to count arrays of nonnegative integers that satisfy a sequence of nested MEX conditions. Concretely, we are given an array a of length n. For each position i in the array, we must ensure that the (n-i+1)-th MEX of the prefix [b1, ..., bi] equals a[i].

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CF 2207E1 - N-MEX (Constructive Version)

We are asked to construct an array b from a given array a such that, for each prefix of b, a generalized MEX condition holds. Specifically, the (n-i+1)-th MEX of the first i elements of b must equal a[i].

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CF 2207D - Boxed Like a Fish

We are given a tree where a token starts at a fixed non-leaf vertex. The goal is to determine whether this token can be guaranteed to reach any leaf vertex if two players act in turns. One player controls the token.

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CF 2207C - Where's My Water?

The grid can be understood more simply if we ignore the 2D picture and focus on each column independently. In column i, there are ai dirt tiles at the bottom, and all tiles above them up to height h are water. So the number of water tiles in column i is h - ai.

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CF 2207A - 1-1

We are given a binary string and a single operation that can be applied repeatedly. The operation only affects positions that are strictly inside the string, and only when that position is surrounded by ones on both sides.

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CF 2207B - One Night At Freddy's

We are asked to simulate a night at Freddy Fazbear’s Pizzeria in terms of danger management. Each animatronic accumulates danger every second, and the night lasts for a fixed number of seconds.