Technocup 2020 - Elimination Round 3

9 problems from Technocup 2020 - Elimination Round 3 (contest 1227), difficulty 1100-2600. 5/9 solutions verified against sample I/O.

9 items

Technocup 2020 - Elimination Round 3

Special | 9 problems | 5/9 verified | Difficulty 1100-2600 | 36m 16s

#	Problem	Rating	Tags	Accepted	Time	✓
A	Math Problem	1100	math	10,264	2m 48s	✓
B	Box	1200	constructive-algorithms	10,429	5m 37s
C	Messy	1700	constructive-algorithms	5,790	5m 39s
D1	Optimal Subsequences (Easy Version)	1600	data-structures, greedy	6,829	3m 5s	✓
D2	Optimal Subsequences (Hard Version)	1800	data-structures, greedy	4,726	2m 52s	✓
E	Arson In Berland Forest	2200	binary-search, graphs, shortest-paths	1,640	3m 41s
F1	Wrong Answer on test 233 (Easy Version)	2200	dp	2,053	2m 19s	✓
F2	Wrong Answer on test 233 (Hard Version)	2400	combinatorics, math	1,919	7m 2s	✓
G	Not Same	2600	constructive-algorithms	1,188	3m 13s

Practice › Codeforces Solutions › Technocup 2020 - Elimination Round 3 ›

CF 1227E - Arson In Berland Forest

The input describes a finite rectangular snapshot of an otherwise infinite grid of trees. Each cell is either burned or intact, and the grid fully contains all burned cells. Outside the grid, everything is guaranteed to be unburned.

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CF 1227G - Not Same

We are given an array where each position stores a pile of blocks. At position i, there are ai identical blocks stacked. One operation consists of choosing some set of positions and removing exactly one block from each chosen position.

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CF 1227F1 - Wrong Answer on test 233 (Easy Version)

We are given a fixed answer key for a multiple-choice test of length n, where each question has a known correct option. We are also considering every possible way to fill in answers for the test, where each position can take any value from 1 to k.

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CF 1227D2 - Optimal Subsequences (Hard Version)

We are given a fixed array of integers and many queries. Each query asks us to imagine picking exactly $k$ elements from the array while preserving their original order. Among all such subsequences of length $k$, we first want the one with the maximum possible sum.

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CF 1227C - Messy

We are given a sequence of parentheses and are allowed to apply an operation that reverses any contiguous segment.

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CF 1227B - Box

We are given a non-decreasing array q, which is claimed to be produced from some hidden permutation p by taking prefix maxima. At every position i, q[i] equals the largest value among the first i elements of p.

Practice › Codeforces Solutions › Technocup 2020 - Elimination Round 3 ›

CF 1227D1 - Optimal Subsequences (Easy Version)

We are given a sequence of numbers and, for each query, we must imagine selecting exactly k elements from this sequence while preserving their original order. Among all such subsequences, we first care about maximizing the sum of chosen values.

Practice › Codeforces Solutions › Technocup 2020 - Elimination Round 3 ›

CF 1227F2 - Wrong Answer on test 233 (Hard Version)

We are given a length-n sequence of questions, and for each position i there is a correct answer h[i]. We construct another sequence a of length n, where each a[i] is chosen independently from 1 to k.

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CF 1227A - Math Problem

We are given several closed intervals on a number line. Each interval represents a set of integer or real points between its endpoints, and the endpoints themselves are included.