9/21 每日一題(檢查是否為遞增或遞減)

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

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

Given an integer array nums, return true if the given array is monotonic, or false otherwise.

 

Example 1:

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

Example 2:

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

Example 3:

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

 

 class Solution:

    def isMonotonic(self, nums: List[int]) -> bool:

        a=0

        b=0

        c=0

        old=nums[0]

        for i in nums[1:]:

            if i > old:

                a=1

            if i < old:

                b=1

            if i==old:

                '相等'

                c+=1

            old=i

        if c==len(nums)-1:

            return True

        if a == b :

            return False

        else:

            return True

--------------------------

class Solution:
    def isMonotonic(self, nums: List[int]) -> bool:
        if len(nums) == 1:
            return True 
        currVal = nums[0]
        desc = False
        incr = False 
        for i in nums:
            if i < currVal:
                desc = True 
            if i > currVal:
                incr = True 
            if incr and desc:
                return False
            currVal = i
        return True