# Arithmetic Sequence Permutation - Amazon Top Interview Questions

### Problem Statement :

```Given a list of integers nums, return whether you can rearrange the order of nums such that the difference between every consecutive two numbers is the same.

Constraints

n ≤ 100,000 where n is the length of nums

Example 1

Input
nums = [7, 1, 5, 3]

Output
True

Explanation
If we rearrange nums to [1, 3, 5, 7], then the difference between every two consecutive numbers is 2.

Example 2

Input
nums = [1, 5, 1, 5, 1, 5]

Output
False

Explanation
The difference between every consecutive two numbers alternates between 4 and -4.```

### Solution :

```                        ```Solution in C++ :

bool solve(vector<int>& nums) {
// Finding Max and Min
int max = nums[0], min = nums[0], max_i = -1, min_i = -1;
for (int i = 1; i < nums.size(); i++) {
if (nums[i] > max) {
max = nums[i];
max_i = i;
}
if (nums[i] < min) {
min = nums[i];
min_i = i;
}
}
if (max - min == 0)  // All numbers same, diff=0
return true;
if ((max - min) % (nums.size() - 1) != 0)  // Case not possible
return false;
// Check for duplicates now
vector<int> freqArr(max + 1, 0);
for (int i = 0; i < nums.size(); i++) {
freqArr[nums[i]] += 1;
if (freqArr[nums[i]] > 1) return false;
}
int min_diff = (max - min) / (nums.size() - 1);
for (int i = 0; i < nums.size(); i++) {
if (i == min_i || i == max_i) continue;
int d2 = nums[i] - min;
if (d2 % min_diff != 0) {
return false;
}
}
return true;
}```
```

```                        ```Solution in Java :

import java.util.*;

class Solution {
public boolean solve(int[] nums) {
Arrays.sort(nums);
for (int i = 2; i < nums.length; i++) {
if (nums[i] - nums[i - 1] != nums[i - 1] - nums[i - 2])
return false;
}
return true;
}
}```
```

```                        ```Solution in Python :

class Solution:
def solve(self, nums):
minima = min(nums)
maxima = max(nums)

d = (maxima - minima) / (len(nums) - 1)
num = minima + d
nums_set = set(nums)
if d == 0:
return True
while num in nums_set:
num += d

if num > maxima:
return True
return False```
```

## Merge two sorted linked lists

This challenge is part of a tutorial track by MyCodeSchool Given pointers to the heads of two sorted linked lists, merge them into a single, sorted linked list. Either head pointer may be null meaning that the corresponding list is empty. Example headA refers to 1 -> 3 -> 7 -> NULL headB refers to 1 -> 2 -> NULL The new list is 1 -> 1 -> 2 -> 3 -> 7 -> NULL. Function Description C

## Get Node Value

This challenge is part of a tutorial track by MyCodeSchool Given a pointer to the head of a linked list and a specific position, determine the data value at that position. Count backwards from the tail node. The tail is at postion 0, its parent is at 1 and so on. Example head refers to 3 -> 2 -> 1 -> 0 -> NULL positionFromTail = 2 Each of the data values matches its distance from the t

## Delete duplicate-value nodes from a sorted linked list

This challenge is part of a tutorial track by MyCodeSchool You are given the pointer to the head node of a sorted linked list, where the data in the nodes is in ascending order. Delete nodes and return a sorted list with each distinct value in the original list. The given head pointer may be null indicating that the list is empty. Example head refers to the first node in the list 1 -> 2 -

## Cycle Detection

A linked list is said to contain a cycle if any node is visited more than once while traversing the list. Given a pointer to the head of a linked list, determine if it contains a cycle. If it does, return 1. Otherwise, return 0. Example head refers 1 -> 2 -> 3 -> NUL The numbers shown are the node numbers, not their data values. There is no cycle in this list so return 0. head refer

## Find Merge Point of Two Lists

This challenge is part of a tutorial track by MyCodeSchool Given pointers to the head nodes of 2 linked lists that merge together at some point, find the node where the two lists merge. The merge point is where both lists point to the same node, i.e. they reference the same memory location. It is guaranteed that the two head nodes will be different, and neither will be NULL. If the lists share

## Inserting a Node Into a Sorted Doubly Linked List

Given a reference to the head of a doubly-linked list and an integer ,data , create a new DoublyLinkedListNode object having data value data and insert it at the proper location to maintain the sort. Example head refers to the list 1 <-> 2 <-> 4 - > NULL. data = 3 Return a reference to the new list: 1 <-> 2 <-> 4 - > NULL , Function Description Complete the sortedInsert function