MORENA - Morenas Candy Shop ( Easy )
HARDER VERSION: www.spoj.com/problems/HILO/
Brunette's is a big candy shop from Little Campina in Paraibas, Brazil. This company is known for making the best candies in the world. Matheus Pheverso is the president of this company and he has a sister called Morena who loves and helps him in running the company. She uses to go the supermarket every day and buy a lot of stuffs to make all the candies. But she's insane and likes to take an alternate path to go to the supermarket.
Given the streets heights, a path is alternate only if the differences between successive numbers strictly alternate between positive and negative.
Example:
- Street Heights: {1, 3, 4, 5, 2, 9, 8, 10}
- Alternate Paths: {1, 3, 2, 9, 8}, {1, 4, 2, 8} {1, 5, 2, 9, 8}
Matheus Pheverso is a friendly brother and he would like to know the longest alternate path between the first supermarket and the last supermarket, this means that his sister always starts at the supermarket number 1, and always ends at the last supermarket.
Given the number of supermarkets, and their heights, your task is to print the longest alternate path between the first and the last city.
Input
There is a single positive integer N on the first line of input (1 <= N <= 10^6) representing the number of supermarkets. In the second line there're N integers Ai representing the heights of each supermarket (-10^18 <= Ai <= 10^18).
Output
You have to print the longest alternate path between the first and the last supermarket. The supermarket number 1 is always the first, and the supermarket number N is always the last one.
Example
Input: 5 1 2 3 4 5 Output 2
Input: 8 1 4 2 10 1 9 7 8 Output 8
hide comments
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shantanu:
2014-05-26 19:48:42
Used dp.. WA. submitted like a thousand times. getting all cases right. Last edit: 2014-07-14 20:29:15 |
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Ouditchya Sinha:
2013-09-11 06:08:00
Awesome Problem! Finally AC!! :) |
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Kevin Sebastian:
2013-07-05 12:05:29
@author I dont understand why I am getting sigsev error submission id 9608166 |
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SWOOSH!!!:
2013-06-29 09:10:30
@mcd10, I cannot understand how my solution is wrong? I have tested it for larger values as well...Submission id 9572459. Last edit: 2013-06-29 09:30:22 |
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Aditya Bahuguna:
2013-06-18 20:13:30
Whoa!//scanf VS cin ..>1 sec time diff |
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Nitin Khanna:
2012-10-16 10:28:02
Can Ai be Negative? If yes what will be output for
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Mateus Dantas [ UFCG ]:
2012-09-30 02:30:28
Yes, the test case:
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:D:
2012-09-29 21:43:01
The definition of the alternating path is the same as for HILO problem. In fact you can convert the data here to:
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le derp!!:
2012-09-20 23:00:03
longest path refer to length here? |
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♘Prabhat:
2012-09-15 11:16:20
can anyone explain why ans of 4 1 1 1 1 is 2 Last edit: 2012-09-16 00:27:18 |
Added by: | Mateus Dantas [ UFCG ] |
Date: | 2012-09-11 |
Time limit: | 1s |
Source limit: | 50000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: ASM64 |