// C++ program to check if a given array // can form arithmetic progression #include    using namespace std; // Checking if array is permutation  // of 0 to n-1 using counting sort bool countingsort(int arr[] int n) {  int count[n] = { 0 };    // Counting the frequency  for (int i = 0; i < n; i++) {  count[arr[i]]++;  }    // Check if each frequency is 1 only  for (int i = 0; i <= n-1; i++) {  if (count[i] != 1)  return false;  }    return true; } // Returns true if a permutation of arr[0..n-1] // can form arithmetic progression bool checkIsAP(int arr[] int n) {  int smallest = INT_MAX second_smallest = INT_MAX;  for (int i = 0; i < n; i++) {    // Find the smallest and   // update second smallest  if (arr[i] < smallest) {  second_smallest = smallest;  smallest = arr[i];  }    // Find second smallest  else if (arr[i] != smallest  && arr[i] < second_smallest)  second_smallest = arr[i];  }  // Find the difference between smallest and second  // smallest  int diff = second_smallest - smallest;  for (int i = 0; i < n; i++) {  arr[i]=arr[i]-smallest;  }    for(int i=0;i<n;i++)  {  if(arr[i]%diff!=0)  {  return false;  }  else  {  arr[i]=arr[i]/diff;  }  }    // If array represents AP it must be a   // permutation of numbers from 0 to n-1.  // Check this using counting sort.  if(countingsort(arrn))  return true;  else  return false; } // Driven Program int main() {  int arr[] = { 20 15 5 0 10 };  int n = sizeof(arr) / sizeof(arr[0]);  (checkIsAP(arr n)) ? (cout << 'Yes' << endl)  : (cout << 'No' << endl);  return 0;  // This code is contributed by Pushpesh Raj } 

// Java program to check if a given array // can form arithmetic progression import java.io.*; class GFG {  // Checking if array is permutation  // of 0 to n-1 using counting sort  static boolean countingsort(int arr[] int n)  {  int[] count = new int[n];  for(int i = 0; i < n; i++)  count[i] = 0;  // Counting the frequency  for (int i = 0; i < n; i++) {  count[arr[i]]++;  }  // Check if each frequency is 1 only  for (int i = 0; i <= n-1; i++) {  if (count[i] != 1)  return false;  }  return true;  }  // Returns true if a permutation of arr[0..n-1]  // can form arithmetic progression  static boolean checkIsAP(int arr[] int n)  {  int smallest = Integer.MAX_VALUE second_smallest = Integer.MAX_VALUE ;  for (int i = 0; i < n; i++) {  // Find the smallest and  // update second smallest  if (arr[i] < smallest) {  second_smallest = smallest;  smallest = arr[i];  }  // Find second smallest  else if (arr[i] != smallest  && arr[i] < second_smallest)  second_smallest = arr[i];  }  // Find the difference between smallest and second  // smallest  int diff = second_smallest - smallest;  for (int i = 0; i < n; i++) {  arr[i] = arr[i] - smallest;  }  for(int i = 0; i < n; i++)  {  if(arr[i] % diff != 0)  {  return false;  }  else  {  arr[i] = arr[i]/diff;  }  }  // If array represents AP it must be a  // permutation of numbers from 0 to n-1.  // Check this using counting sort.  if(countingsort(arrn))  return true;  else  return false;  }  // Driven Program  public static void main (String[] args)  {  int arr[] = { 20 15 5 0 10 };  int n = arr.length;  if(checkIsAP(arr n))   System.out.println('Yes');  else System.out.println('No');  } } // This code is contributed by Utkarsh 

# Python program to check if a given array # can form arithmetic progression import sys # Checking if array is permutation  # of 0 to n-1 using counting sort def countingsort( arr n): count = [0]*n; # Counting the frequency for i in range(0 n): count[arr[i]] += 1; # Check if each frequency is 1 only for i in range(0 n - 1): if (count[i] != 1): return False; return True; # Returns true if a permutation of arr[0..n-1] # can form arithmetic progression def checkIsAP( arr n): smallest = sys.maxsize; second_smallest = sys.maxsize; for i in range(0n): # Find the smallest and  # update second smallest if (arr[i] < smallest) : second_smallest = smallest; smallest = arr[i]; # Find second smallest elif (arr[i] != smallest and arr[i] < second_smallest): second_smallest = arr[i]; # Find the difference between smallest and second # smallest diff = second_smallest - smallest; for i in range(0n): arr[i]=arr[i]-smallest; for i in range(0n): if(arr[i]%diff!=0): return False; else: arr[i]=(int)(arr[i]/diff); # If array represents AP it must be a  # permutation of numbers from 0 to n-1. # Check this using counting sort. if(countingsort(arrn)): return True; else: return False; # Driven Program arr = [ 20 15 5 0 10 ]; n = len(arr); if(checkIsAP(arr n)): print('Yes'); else: print('NO'); # This code is contributed by ratiagrawal. 

using System;  class GFG  {  // Checking if array is permutation  // of 0 to n-1 using counting sort  static bool CountingSort(int[] arr int n)  {  // Counting the frequency  int[] count = new int[n];  for (int i = 0; i < n; i++)  {  count[arr[i]]++;  }  // Check if each frequency is 1 only  for (int i = 0; i <= n - 1; i++)  {  if (count[i] != 1)  {  return false;  }  }  return true;  }// Returns true if a permutation of arr[0..n-1]  // can form arithmetic progression  static bool CheckIsAP(int[] arr int n)  {// Find the smallest and  // update second smallest  int smallest = int.MaxValue;  int secondSmallest = int.MaxValue;  for (int i = 0; i < n; i++)  {  if (arr[i] < smallest)  {  secondSmallest = smallest;  smallest = arr[i];  }  else if (arr[i] != smallest && arr[i] < secondSmallest)  {  secondSmallest = arr[i];  }  }  int diff = secondSmallest - smallest;  for (int i = 0; i < n; i++)  {  arr[i] = arr[i] - smallest;  }  for (int i = 0; i < n; i++)  {  if (arr[i] % diff != 0)  {  return false;  }  else  {  arr[i] = arr[i] / diff;  }  } // If array represents AP it must be a  // permutation of numbers from 0 to n-1.  // Check this using counting sort.  if (CountingSort(arr n))  {  return true;  }  else  {  return false;  }  } // Driven Program  static void Main(string[] args)  {  int[] arr = new int[] { 20 15 5 0 10 };  int n = arr.Length;  Console.WriteLine(CheckIsAP(arr n) ? 'Yes' : 'No');  }  } 

// Javascript program to check if a given array // can form arithmetic progression // Checking if array is permutation  // of 0 to n-1 using counting sort function countingsort( arr n) {  let count=new Array(n).fill(0);    // Counting the frequency  for (let i = 0; i < n; i++) {  count[arr[i]]++;  }    // Check if each frequency is 1 only  for (let i = 0; i <= n-1; i++) {  if (count[i] != 1)  return false;  }    return true; } // Returns true if a permutation of arr[0..n-1] // can form arithmetic progression function checkIsAP( arr n) {  let smallest = Number.MAX_SAFE_INTEGER second_smallest = Number.MAX_SAFE_INTEGER;  for (let i = 0; i < n; i++) {    // Find the smallest and   // update second smallest  if (arr[i] < smallest) {  second_smallest = smallest;  smallest = arr[i];  }    // Find second smallest  else if (arr[i] != smallest  && arr[i] < second_smallest)  second_smallest = arr[i];  }  // Find the difference between smallest and second  // smallest  let diff = second_smallest - smallest;  for (let i = 0; i < n; i++) {  arr[i]=arr[i]-smallest;  }    for(let i=0;i<n;i++)  {  if(arr[i]%diff!=0)  {  return false;  }  else  {  arr[i]=arr[i]/diff;  }  }    // If array represents AP it must be a   // permutation of numbers from 0 to n-1.  // Check this using counting sort.  if(countingsort(arrn))  return true;  else  return false; } // Driven Program let arr = [20 15 5 0 10 ]; let n = arr.length; (checkIsAP(arr n)) ? (console.log('Yesn'))  : (console.log('Non'));    // // This code was contributed by poojaagrawal2. 

// C++ program for above approach #include    using namespace std; bool checkIsAP(int arr[] int n) {  unordered_set<int> st;  int maxi = INT_MIN;  int mini = INT_MAX;  for (int i=0;i<n;i++) {  maxi = max(arr[i] maxi);  mini = min(arr[i] mini);  st.insert(arr[i]);  }    // FINDING THE COMMON DIFFERENCE  int diff = (maxi - mini) / (n - 1);  int count = 0;  // CHECK TERMS OF AP PRESENT IN THE HASHSET  while (st.find(maxi)!=st.end()) {  count++;  maxi = maxi - diff;  }    if (count == n)  return true;  return false; } // Driver Code int main() {  int arr[] = { 0 12 4 8 };  int n = 4;  cout << boolalpha << checkIsAP(arr n);  return 0; } // This code is contributed by Rohit Pradhan 

/*package whatever //do not write package name here */ import java.io.*; import java.util.*; class GFG {  public static void main(String[] args)  {  int[] arr = { 0 12 4 8 };  int n = arr.length;  System.out.println(checkIsAP(arr n));  }  static boolean checkIsAP(int arr[] int n)  {  HashSet<Integer> set = new HashSet<Integer>();  int max = Integer.MIN_VALUE;  int min = Integer.MAX_VALUE;  for (int i : arr) {  max = Math.max(i max);  min = Math.min(i min);  set.add(i);  }    // FINDING THE COMMON DIFFERENCE  int diff = (max - min) / (n - 1);  int count = 0;  // CHECK IF TERMS OF AP PRESENT IN THE HASHSET   while (set.contains(max)) {  count++;  max = max - diff;  }  if (count == arr.length)  return true;  return false;  } } 

import sys def checkIsAP(arr n): Set = set() Max = -sys.maxsize - 1 Min = sys.maxsize for i in arr: Max = max(i Max) Min = min(i Min) Set.add(i) # FINDING THE COMMON DIFFERENCE diff = (Max - Min) // (n - 1) count = 0 # CHECK IF TERMS OF AP PRESENT IN THE HASHSET  while (Max in Set): count += 1 Max = Max - diff if (count == len(arr)): return True return False # driver code arr = [ 0 12 4 8 ] n = len(arr) print(checkIsAP(arr n)) # This code is contributed by shinjanpatra 

using System; using System.Collections.Generic; public class GFG  {  // C# program for above approach  static bool checkIsAP(int[] arr int n)  {  HashSet<int> st = new HashSet<int>();  int maxi = int.MinValue;  int mini = int.MaxValue;  for (int i = 0; i < n; i++) {  maxi = Math.Max(arr[i] maxi);  mini = Math.Min(arr[i] mini);  st.Add(arr[i]);  }    // FINDING THE COMMON DIFFERENCE  int diff = (maxi - mini) / (n - 1);  int count = 0;  // CHECK IF TERMS OF AP PRESENT IN THE HASHSET   while (st.Contains(maxi)) {  count++;  maxi = maxi - diff;  }  if (count == n) {  return true;  }  return false;  }  // Driver Code  internal static void Main()  {  int[] arr = { 0 12 4 8 };  int n = 4;  Console.Write(checkIsAP(arr n));  }  // This code is contributed by Aarti_Rathi } 

function checkIsAP(arr n){  set = new Set()  let Max = Number.MIN_VALUE  let Min = Number.MAX_VALUE  for(let i of arr){  Max = Math.max(i Max)  Min = Math.min(i Min)  set.add(i)  }    // FINDING THE COMMON DIFFERENCE  let diff = Math.floor((Max - Min) / (n - 1))  let count = 0  // CHECK IF TERMS OF AP PRESENT IN THE HASHSET   while (set.has(Max)){  count += 1  Max = Max - diff  }  if (count == arr.length)  return true  return false } // driver code let arr = [ 0 12 4 8 ] let n = arr.length console.log(checkIsAP(arr n))