3392. Count-Subarrays-Of-Length-Three-With-A-Condition

YIPPEE an easy question!

Since the length of the array is bounded at 100, we can brute force this problem. Go through all the subarrays of length 3 and check if they meet the condition.

We return the total number of valid subarrays.

class Solution(object):
    def countSubarrays(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        res = 0
        for i in range(len(nums) - 2):
            if (nums[i] + nums[i + 2]) * 2 == nums[i + 1]:
                res += 1
        return res

Time Complexity: O(n)

Space Complexity: O(1)

Time Taken: 2m 19s