Codeforces Round 279 (Div. 2)

6 problems from Codeforces Round 279 (Div. 2) (contest 490), difficulty 800-2200. 4/6 solutions verified against sample I/O.

6 items

Codeforces Round 279 (Div. 2)

Div. 2 | 6 problems | 4/6 verified | Difficulty 800-2200 | 12m 6s

#	Problem	Rating	Tags	Accepted	Time	✓
A	Team Olympiad	800	greedy, implementation, sortings	70,942	1m 57s
B	Queue	1500	dsu, implementation	6,422	2m 47s
C	Hacking Cypher	1700	brute-force, math, number-theory	9,472	2m 23s	✓
D	Chocolate	1900	brute-force, dfs-and-similar, math	2,314	1m 25s	✓
E	Restoring Increasing Sequence	2000	binary-search, brute-force, greedy	1,699	2m 6s	✓
F	Treeland Tour	2200	data-structures, dfs-and-similar, dp	1,913	1m 28s	✓

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CF 490E - Restoring Increasing Sequence

We are given a sequence of strings. Each string represents a positive integer, but some digits have been replaced by '?'. The original sequence was strictly increasing. Our task is to replace every '?

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CF 490F - Treeland Tour

We are given a tree of cities, where each city has a population. The roads connect cities such that there is exactly one simple path between any two cities.

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CF 490D - Chocolate

Each chocolate bar is a rectangle made of unit squares, so its “value” is just its area. We start with two rectangles and we are allowed to modify them minute by minute.

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CF 490B - Queue

Each input line describes one student, but the student's own ID is not given directly. Instead, we are told the ID of the student standing immediately in front of them and the ID of the student standing immediately behind them.

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CF 490C - Hacking Cypher

We are given a very long decimal number as a string. Its length can reach one million digits, so treating it as a normal integer is impossible. We must choose a position where the string is cut into two nonempty pieces.

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CF 490A - Team Olympiad

We are given a list of children, each identified by a number indicating their skill: programming (1), maths (2), or physical education (3). The task is to form as many teams of three as possible, where each team has exactly one child from each skill.