Editorial of Educational Codeforces Round 16

Правка en3, от Edvard, 2016-08-30 00:04:38

710A - Ходы короля

Easy to see that there are only three cases in this problem. If the king is in the corner of the board the answer is 3. If the king is on the border of the board but not in a corner then the answer is 5. Otherwise the answer is 8.

С++ solution

Complexity: O(1).

710B - Оптимальная точка на прямой

The function of the total distance is monotonic between any pair of adjacent points from the input, so the answer is always in some of the given points. We can use that observation to solve the problem by calculating the total distance for each point from the input and finding the optimal point.

The other solution uses the observation that the answer is always is the middle point (by index) in the sorted list of the given points. The last fact is also can be easily proven.

C++ solution

Complexity: O(nlogn).

710C - Магический нечётный квадрат

The problem was suggested by Resul Hangeldiyev Resul.

The solution can be got from the second sample testcase. Easy to see that if we place all odd numbers in the center in form of rhombus we will get a magic square.

C++ solution

Complexity: O(n2).

Теги educational round 16, editorial

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  Rev. Язык Кто Когда Δ Комментарий
en6 Английский Edvard 2016-08-30 01:56:47 4835
en5 Английский Edvard 2016-08-30 01:11:02 1545
en4 Английский Edvard 2016-08-30 00:41:38 1965
en3 Английский Edvard 2016-08-30 00:04:38 2 Tiny change: 'ncorner than the answ' -> 'ncorner then the answ'
en2 Английский Edvard 2016-08-30 00:03:23 945
en1 Английский Edvard 2016-08-29 23:57:58 1839 Initial revision for English translation
ru4 Русский Edvard 2016-08-25 01:51:17 4900 Мелкая правка: 'ность: $O(slen\cdot logm)$, гд' -
ru3 Русский Edvard 2016-08-25 01:37:55 1633
ru2 Русский Edvard 2016-08-25 01:24:39 1967 Мелкая правка: 'уравнение получается решается ' -> 'уравнение решается '
ru1 Русский Edvard 2016-08-25 01:08:13 2829 Первая редакция (опубликовано)