**Insert Into Linked List - Facebook Top Interview Questions**

### Problem Statement :

You are given a singly linked list head as well as integers pos and val. Insert a new node with value val before index pos of head. Constraints 1 ≤ n ≤ 100,000 where n is the number of nodes in head 0 ≤ pos ≤ n Example 1 Input head = [1, 3, 5, 7] pos = 2 val = 9 Output [1, 3, 9, 5, 7] Example 2 Input head = [1] pos = 0 val = 3 Output [3, 1] Example 3 Input head = [2] pos = 1 val = 5 Output [2, 5]

### Solution :

` ````
Solution in C++ :
LLNode* solve(LLNode* head, int pos, int val) {
auto dum = new LLNode(-1, head), prev = dum;
while (pos--) {
prev = head;
head = head->next;
}
LLNode* temp = new LLNode(val, head);
prev->next = temp;
return dum->next;
}
```

` ````
Solution in Java :
import java.util.*;
/**
* class LLNode {
* int val;
* LLNode next;
* }
*/
class Solution {
public LLNode solve(LLNode head, int pos, int val) {
if (pos == 0) {
LLNode ans = new LLNode(val, head);
return ans;
}
LLNode temp = head;
while (pos > 1) {
temp = temp.next;
pos--;
}
temp.next = new LLNode(val, temp.next);
return head;
}
}
```

` ````
Solution in Python :
class Solution:
def solve(self, head, pos, val):
new = LLNode(val)
if pos == 0:
new.next = head
return new
temp = head
while temp and pos != 1:
temp = temp.next
pos -= 1
new.next = temp.next
temp.next = new
return head
```

## View More Similar Problems

## Queries with Fixed Length

Consider an -integer sequence, . We perform a query on by using an integer, , to calculate the result of the following expression: In other words, if we let , then you need to calculate . Given and queries, return a list of answers to each query. Example The first query uses all of the subarrays of length : . The maxima of the subarrays are . The minimum of these is . The secon

View Solution →## QHEAP1

This question is designed to help you get a better understanding of basic heap operations. You will be given queries of types: " 1 v " - Add an element to the heap. " 2 v " - Delete the element from the heap. "3" - Print the minimum of all the elements in the heap. NOTE: It is guaranteed that the element to be deleted will be there in the heap. Also, at any instant, only distinct element

View Solution →## Jesse and Cookies

Jesse loves cookies. He wants the sweetness of all his cookies to be greater than value K. To do this, Jesse repeatedly mixes two cookies with the least sweetness. He creates a special combined cookie with: sweetness Least sweet cookie 2nd least sweet cookie). He repeats this procedure until all the cookies in his collection have a sweetness > = K. You are given Jesse's cookies. Print t

View Solution →## Find the Running Median

The median of a set of integers is the midpoint value of the data set for which an equal number of integers are less than and greater than the value. To find the median, you must first sort your set of integers in non-decreasing order, then: If your set contains an odd number of elements, the median is the middle element of the sorted sample. In the sorted set { 1, 2, 3 } , 2 is the median.

View Solution →## Minimum Average Waiting Time

Tieu owns a pizza restaurant and he manages it in his own way. While in a normal restaurant, a customer is served by following the first-come, first-served rule, Tieu simply minimizes the average waiting time of his customers. So he gets to decide who is served first, regardless of how sooner or later a person comes. Different kinds of pizzas take different amounts of time to cook. Also, once h

View Solution →## Merging Communities

People connect with each other in a social network. A connection between Person I and Person J is represented as . When two persons belonging to different communities connect, the net effect is the merger of both communities which I and J belongs to. At the beginning, there are N people representing N communities. Suppose person 1 and 2 connected and later 2 and 3 connected, then ,1 , 2 and 3 w

View Solution →