Maximum length bitonic subarray

#1

This code does not pass all the test cases, why?

#2

hello @ayushtiwari12

the question is asking for maximum lenght bitonic subarray

but ur solution will find maximum lenght bitonic sub sebsequence

in case of subarray the elements should be present in consective indices.

#3

@ayushtiwari12

We create two arrays - ‘inc’ and ‘dec’

  1. inc[i] stores the length of increasing subarray till i.
  2. dec[i] stores the length of decreasing subarray starting from index i.
  3. Doing so gives us the length of increasing and decreasing subarray at each index in O(n) time.
  4. We calculate the length of the longest bitonic subarray by finding the maximum inc[i] + dec[i] - 1
  5. We subtract one since the current element at ith index is included in both the increasing and decreasing subarray lengths.

Algorithm

  1. Initialize inc[0] to 1 and dec[n-1] to 1
  2. Creating inc[] array
    a. Till end of the array ie, i=1 to n, if arr[i] > arr[i-1] then inc[i] = inc[i-1] + 1. else, inc[i] = 1
  3. Creating dec[] array
    a. From the end of the array ie, i = n-2 till i =0, if arr[i] > arr[i+1] then dec[i] = dec[i+1] +1 else, dec[i] = 1.
Doubt doubt doubt
#4

I’m still facing problem can you tell me via my code.

#5

@ayushtiwari12
pls refer this->

#6

Thankyou for explaining, now I got it.