334.md

334. Increasing Triplet Subsequence

Solution 1 (time O(n), space O(1))

class Solution(object):
    def increasingTriplet(self, nums):
        """
        :type nums: List[int]
        :rtype: bool
        """
        n = len(nums)
        if n < 3:
            return False
        num1, num2 = nums[0], float("inf")
        for i in range(1, n):
            if nums[i] > num2:
                return True
            elif nums[i] > num1:
                num2 = nums[i]
            else:
                num1 = nums[i]
        return False