Lunski's Clutter

You are given an array of k linked-lists lists, each linked-list is sorted in ascending order.

Merge all the linked-lists into one sorted linked-list and return it.

Example 1:

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Input: lists = [[1,4,5],[1,3,4],[2,6]]
Output: [1,1,2,3,4,4,5,6]
Explanation: The linked-lists are:
[
  1->4->5,
  1->3->4,
  2->6
]
merging them into one sorted list:
1->1->2->3->4->4->5->6

Example 2:

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Input: lists = []
Output: []
Example 3:

Input: lists = [[]]
Output: []

Merge two sorted linked lists and return it as a sorted list. The list should be made by splicing together the nodes of the first two lists.

Example 1:

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Input: l1 = [1,2,4], l2 = [1,3,4]
Output: [1,1,2,3,4,4]

Example 2:

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Input: l1 = [], l2 = []
Output: []

Example 3:

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Input: l1 = [], l2 = [0]
Output: [0]

Given a string s containing just the characters ‘(‘, ‘)’, ‘{‘, ‘}’, ‘[‘ and ‘]’, determine if the input string is valid.

An input string is valid if:

Open brackets must be closed by the same type of brackets.
Open brackets must be closed in the correct order.

Example 1:

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Input: s = "()"
Output: true

Example 2:

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Input: s = "()[]{}"
Output: true

Example 3:

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Input: s = "(]"
Output: false

Example 4:

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Input: s = "([)]"
Output: false

Example 5:

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Input: s = "{[]}"
Output: true

Given an array nums of n integers, are there elements a, b, c in nums such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero.

Notice that the solution set must not contain duplicate triplets.

Example 1:

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Input: nums = [-1,0,1,2,-1,-4]
Output: [[-1,-1,2],[-1,0,1]]

Example 2:

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Input: nums = []
Output: []

Example 3:

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Input: nums = [0]
Output: []

Given the head of a linked list, remove the nth node from the end of the list and return its head.

Follow up: Could you do this in one pass?

Example 1:

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Input: head = [1,2,3,4,5], n = 2
Output: [1,2,3,5]

Example 2:

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Input: head = [1], n = 1
Output: []

Example 3:

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Input: head = [1,2], n = 1
Output: [1]