Monotonic Array.py

'''
An array is monotonic if it is either monotone increasing or monotone decreasing.

An array A is monotone increasing if for all i <= j, A[i] <= A[j].  An array A is monotone decreasing if for all i <= j, A[i] >= A[j].

Return true if and only if the given array A is monotonic.

 

Example 1:

Input: [1,2,2,3]
Output: true

Example 2:

Input: [6,5,4,4]
Output: true

Example 3:

Input: [1,3,2]
Output: false

Example 4:

Input: [1,2,4,5]
Output: true

Example 5:

Input: [1,1,1]
Output: true

 

Note:

    1 <= A.length <= 50000
    -100000 <= A[i] <= 100000


'''

class Solution(object):
    def isMonotonic(self, A):
        """
        :type A: List[int]
        :rtype: bool
        """
        up_count = 0
        down_count = 0
        for i in xrange(len(A)-1):
            if A[i] <= A[i+1]:
                up_count += 1
            if A[i] >= A[i+1]:
                down_count += 1
        if up_count == len(A)-1 or down_count == len(A)-1:
            return True
        return False