491\. Increasing Subsequences

Medium

Given an integer array `nums`, return all the different possible increasing subsequences of the given array with **at least two elements**. You may return the answer in **any order**.

The given array may contain duplicates, and two equal integers should also be considered a special case of increasing sequence.

**Example 1:**

**Input:** nums = [4,6,7,7]

**Output:** [[4,6],[4,6,7],[4,6,7,7],[4,7],[4,7,7],[6,7],[6,7,7],[7,7]]

**Example 2:**

**Input:** nums = [4,4,3,2,1]

**Output:** [[4,4]]

**Constraints:**

*   `1 <= nums.length <= 15`
*   `-100 <= nums[i] <= 100`