Leetcode 941 - Valid Mountain Array solution

Solution:

The strategy is to check for an increasing order and then a decreasing order. We need to check for the length of the current pointer after each loop.

class Solution:
    def validMountainArray(self, arr: List[int]) -> bool:
        lenght = len(arr)
        
        if lenght < 3:
            return False
        
        i = 1
        
        while i < lenght:
            if arr[i-1] < arr[i]:
                i += 1
            else:
                break

        if i == lenght or i == 1:
            return False
        
        while i < lenght:
            if arr[i-1] > arr[i]:
                i += 1
            else:
                break
   
        if i != lenght:
            return False
        
        return True

Can you see the problem here? You got it, we can simplofy the while logic right..

class Solution:
   def validMountainArray(self, arr: List[int]) -> bool:
       lenght = len(arr)
       
       if lenght < 3:
           return False
       
       i = 1
       
       while i < lenght and arr[i-1] < arr[i]:
           i += 1

       if i == lenght or i == 1:
           return False
       
       while i < lenght and arr[i-1] > arr[i]:
           i += 1
  
       return i == lenght