0659. Split Array into Consecutive Subsequences

https://leetcode.com/problems/split-array-into-consecutive-subsequences

Description

You are given an integer array nums that is sorted in non-decreasing order.

Determine if it is possible to split nums into one or more subsequences such that both of the following conditions are true:

• Each subsequence is a consecutive increasing sequence (i.e. each integer is exactly one more than the previous integer).

• All subsequences have a length of 3 or more.

Return true if you can split nums according to the above conditions, or false otherwise.

A subsequence of an array is a new array that is formed from the original array by deleting some (can be none) of the elements without disturbing the relative positions of the remaining elements. (i.e., [1,3,5] is a subsequence of [1,2,3,4,5] while [1,3,2] is not).

Example 1:

**Input:** nums = [1,2,3,3,4,5]
**Output:** true
**Explanation:** nums can be split into the following subsequences:
[**1**,**2**,**3**,3,4,5] --> 1, 2, 3
[1,2,3,**3**,**4**,**5**] --> 3, 4, 5

Example 2:

**Input:** nums = [1,2,3,3,4,4,5,5]
**Output:** true
**Explanation:** nums can be split into the following subsequences:
[**1**,**2**,**3**,3,**4**,4,**5**,5] --> 1, 2, 3, 4, 5
[1,2,3,**3**,4,**4**,5,**5**] --> 3, 4, 5

Example 3:

**Input:** nums = [1,2,3,4,4,5]
**Output:** false
**Explanation:** It is impossible to split nums into consecutive increasing subsequences of length 3 or more.

Constraints:

• 1 <= nums.length <= 104

• -1000 <= nums[i] <= 1000

• nums is sorted in non-decreasing order.

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