HomeVolumesContestsSectionsForumsUsersPrintHelpAbout

Volumes > Array and Matrices > problem:


50419 - The longest bitonic sequence

Guest
• Review clarifications (3)

Volume problems

• 50445 - Cryptography
• 50410 - Zero Padding
• 50380 - Sum of the Numbers in the ...
• 50400 - nth Row rth Element of a Table
• 50457 - The Number of Winners
• 50585 - Inner Product
• 50587 - Modular Conversion
• 030. 50737 - Sum of the k-largest n...
• 50419 - The longest bitonic seq...
• 50317 - Student Line Up
• 50311 - Student Line Up
• 50398 - Sum of kth Anti-diagonal
• 50323 - Filtering Contact List
• 50364 - Student averages
• 50756 - Average of the Nth Student
• 50758 - National Elections - Revisited
• 50458 - Weekly Report

Feedback

If you notice incorrect translations in Contester, please let author know.

Time limit 2000/4000/4000/4000 ms. Memory limit 2000/64000/15000/15000 Kb.
Question by Ilir Capuni.

The longest bitonic sequence

A sequence of integers whose values first increase and reach the peek, and then decrease is called bitonic. In this problem, we are looking at bitonic sequences of a given sequence.
Note: Increasing (and decreasing) doesn't include equal to. When it's increasing, the current number is definitely greater than the previous number.

Example:
The sequence 1 2 4 6 8 7 5 4 3 2 1 is bitonic, with number 8 being the peek. A sequence of this sequence is, say 1 6 5 1, but 8 2 6 is not a sequence.

Suppose that you are given an array of integers. You need to find the length of the longest bitonic sequence of the given sequence.

Question:
Write a program that gets as an input a positive number n and a sequence of n integers and computes the length of the longest bitonic sequence.

Input specification
You will be given an integer number (n) at the beginning where 1 ≤ n ≤ 50000. Then, in the following line, you will be given n integers which are between -10000 and 10000.

Output specification
Show just one integer: length of the longest bitonic sequence.

 Sample Input I   
  6
  3 0 1 4 2 -1
 Sample Input II   
  14
  4 2 1 5 7 3 1 4 7 8 2 1 3 2
 Sample Output I   
  5
 Sample Output II   
  6

Explanation for Sample Input 2: The longest bitonic sequence is: 1 4 7 8 2 1 with the length 6.

Для отправки решений необходимо выполнить вход.

www.contester.ru