# Week 3: Linked Lists

#### 0) Operations of Single LLs

Node { node next; int value; }

Node.next = pointer to next node Node.value = value of node

Head: first node in list Tail: last node in list (Node.next = NULL)

#### 1) Remove Kth node from Single LL

Given a linked list, remove the k-th node of the list and return its head.

```
Input: 1->2->3->4->5, and k = 2.
Output: link list 1->2->4->5.
```

```
Input: 1->3->5->7, and k = 0.
Output: linked list 3->5->7
```

#### 2) Remove Kth node from end of Single LL

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

```
Input: 1->2->3->4->5, and k = 1.
Output: linked list 1->2->3->5.
```

```
Input: 1->2->3, and k = 0
Output: linked list 1->2
```

#### 3) Merge 2 sorted LL

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

```
Input: 1->2->4, 1->3->4
Output: 1->1->2->3->4->4
```

–HARD–

### 4) Rotate LL

Given the head of a linked list, rotate the list to the right by k places.

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

```
Input: head = [0,1,2], k = 4
Output: [2,0,1]
```

### 5) Add Two Numbers

You are given two **non-empty** linked lists representing two non-negative integers. The digits are stored in **reverse order**, and each of their nodes contains a single digit. Add the two numbers and return the sum as a linked list.

You may assume the two numbers do not contain any leading zero, except the number 0 itself.

```
Input: l1 = [2,4,3], l2 = [5,6,4]
Output: [7,0,8]
Explanation: 342 + 465 = 807
```

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

```
Input: l1 = [9,9,9,9,9,9,9], l2 = [9,9,9,9]
Output: [8,9,9,9,0,0,0,1]
```

Constraints:

- The number of nodes in each linked list is in the range
`[1, 100]`

. `0 <= Node.val <= 9`

- It is guaranteed that the list represents a number that does not have leading zeros.