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| Показать все ветки Спрятать все ветки Показать все сообщения Спрятать все сообщения | | Hint for solution | Vlad | 1699. Черепахи и повороты | 17 авг 2022 10:36 | 6 | This was overall a great problems set!
Can anyone give a hint on the solution for "J. Turning Turtles"?
What special property (beside that it's a tree) must one use?
What is the complexity of the intended solution?
Thanks in advance! This problem can be solved in O(N + Q*logN), where N is the size of the field. Am I right that we build slightly another tree and then use LCA on that? =)
And when the problems will be added to the problemset? Actually it is possible to use the given tree. But calculating the answer is not very trivial. I was glad to use successfully LCA
with forgotten implementation.
It is enough to know what LCA do.
It is mean that LCA very adequate tool for tree
and cannot be omitted in learning. It is possible to use given tree, but my complexity is O(N*log(N)+Q*log(N)) - 0.25 sec and quite a bunch of RAM. For every node store its 1st, 2nd, 4th, 8th, 16th, ... 2^16th parent. Also store number of turns on that path and final orientation after last move (horizontal/vertical). This information is enough to calculate answers at log(N). | | Have wa #12 | cap_prot | 1699. Черепахи и повороты | 6 авг 2013 19:17 | 2 | My program is more advanced than LCA. It uses BFS and could work on arbitrary graphs. Could somebody help with this test? I know that if there is no bug with my program then there is a problem with connectivity of graph from start point to end point. Check for cases when start = end.
also don't use incorrect comparison. for example:
newPoint = point+delta
if(0<=newPoint && newPoint<w*h) | | wa #7 | Baurzhan | 1699. Черепахи и повороты | 27 янв 2013 18:40 | 3 | wa #7 Baurzhan 5 ноя 2010 19:40 Who had problems with test #7, tell me WTF? Please,anybody,post here some tricky tests! This test helped me to avoid WA#7:
6 6
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#.#.#.
#.#.##
#.....
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#.#..#
1
3 6 6 6
ans: 6 Right answer is 5, isn't it?
Edited by author 27.01.2013 18:40 | | For those who has problems with test #4 | Vedernikoff Sergey (HSE: EconomicsForever!) | 1699. Черепахи и повороты | 16 мар 2009 01:44 | 1 | Try this test:
INPUT
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1 1
#
2
1 1 1 1
1 1 1 1
OUTPUT
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0
0
Edited by author 16.03.2009 15:10 |
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