The problem. Given an integer array nums, return true if there are three indexes i < j < k with nums[i] < nums[j] < nums[k] — three values that increase from left to right — and false otherwise. They don't need to be next to each other. The follow-up asks for O(n) time and O(1) space.
![The array [2, 1, 5, 0, 4, 6]. The values 1, 4 and 6 at indexes 1, 4 and 5 increase from left to right, so the answer is true.](/drawings/715139b7-ada8-4fac-ac6c-b425f403c23c.svg)
Input: nums = [1, 2, 3, 4, 5]
Output: true e.g. 1 < 2 < 3
Input: nums = [5, 4, 3, 2, 1]
Output: false the values only fall
Input: nums = [2, 1, 5, 0, 4, 6]
Output: true e.g. 1 < 4 < 6, or 0 < 4 < 6Free account
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