class Solution:
    def isMonotonic(self, nums: List[int]) -> bool:
        direction = 0
        prev = nums[0]
        
        for num in nums[1:]:
            newDirection = num - prev
            
            if direction == 0:
                direction = newDirection
            elif direction < 0 < newDirection or direction > 0 > newDirection:
                return False
            
            prev = num
        
        return True