Find element in array that divides all array elements
Last Updated :
19 Apr, 2023
Given an array of n non-negative integers. Find such element in the array, that all array elements are divisible by it.
Examples :
Input : arr[] = {2, 2, 4}
Output : 2
Input : arr[] = {2, 1, 3, 1, 6}
Output : 1
Input: arr[] = {2, 3, 5}
Output : -1
Brute Force Approach:
The brute force approach to solve this problem would be to iterate through all the elements of the array and check if any of them can divide all other elements of the array. If such a number is found, return it as the answer. Otherwise, return -1 as no such number exists.
Below is the implementation of the above approach:
C++
// CPP program to find such number in the array
// that all array elements are divisible by it
#include <bits/stdc++.h>
using namespace std;
// Function to return the
// desired number if exists
int findNumber(int arr[], int n)
{
for (int i = 0; i < n; i++) {
int j;
for (j = 0; j < n; j++)
if (arr[j] % arr[i] != 0)
break;
if (j == n)
return arr[i];
}
return -1;
}
// Driver Function
int main()
{
int arr[] = { 2, 2, 4 };
int n = sizeof(arr) / sizeof(arr[0]);
cout << findNumber(arr, n) << endl;
return 0;
}
import java.util.*;
public class Main {
// Function to return the
// desired number if exists
static int findNumber(int arr[], int n) {
for (int i = 0; i < n; i++) {
int j;
for (j = 0; j < n; j++) {
if (arr[j] % arr[i] != 0)
break;
}
if (j == n)
return arr[i];
}
return -1;
}
// Driver Function
public static void main(String[] args) {
int arr[] = { 2, 2, 4 };
int n = arr.length;
System.out.println(findNumber(arr, n));
}
}
# Function to return the
# desired number if exists
def findNumber(arr):
n = len(arr)
for i in range(n):
j = 0
while j < n:
if arr[j] % arr[i] != 0:
break
j += 1
if j == n:
return arr[i]
return -1
# Driver Function
arr = [2, 2, 4]
print(findNumber(arr))
using System;
class MainClass {
// Function to return the
// desired number if exists
public static int FindNumber(int[] arr)
{
for (int i = 0; i < arr.Length; i++) {
int j;
for (j = 0; j < arr.Length; j++)
if (arr[j] % arr[i] != 0)
break;
if (j == arr.Length)
return arr[i];
}
return -1;
}
// Driver Function
public static void Main(string[] args)
{
int[] arr = { 2, 2, 4 };
Console.WriteLine(FindNumber(arr));
}
}
// Function to return the desired number if exists
function findNumber(arr, n) {
for (let i = 0; i < n; i++) {
let j;
for (j = 0; j < n; j++)
if (arr[j] % arr[i] != 0)
break;
if (j == n)
return arr[i];
}
return -1;
}
let arr = [2, 2, 4];
let n = arr.length;
console.log(findNumber(arr, n));
Output: 2
Time Complexity: O(N^2)
Space Complexity: O(1)
The approach is to calculate GCD of the entire array and then check if there exist an element equal to the GCD of the array. For calculating the gcd of the entire array we will use Euclidean algorithm.
Implementation:
C++
// CPP program to find such number in the array
// that all array elements are divisible by it
#include <bits/stdc++.h>
using namespace std;
// Returns gcd of two numbers.
int gcd(int a, int b)
{
if (a == 0)
return b;
return gcd(b % a, a);
}
// Function to return the
// desired number if exists
int findNumber(int arr[], int n)
{
// Find GCD of array
int ans = arr[0];
for (int i = 0; i < n; i++)
ans = gcd(ans, arr[i]);
// Check if GCD is present in array
for (int i = 0; i < n; i++)
if (arr[i] == ans)
return ans;
return -1;
}
// Driver Function
int main()
{
int arr[] = { 2, 2, 4 };
int n = sizeof(arr) / sizeof(arr[0]);
cout << findNumber(arr, n) << endl;
return 0;
}
// JAVA program to find such number in
// the array that all array elements
// are divisible by it
import java.io.*;
class GFG {
// Returns GCD of two numbers
static int gcd(int a, int b)
{
if (a == 0)
return b;
return gcd(b % a, a);
}
// Function to return the desired
// number if exists
static int findNumber(int arr[], int n)
{
// Find GCD of array
int ans = arr[0];
for (int i = 0; i < n; i++)
ans = gcd(ans, arr[i]);
// Check if GCD is present in array
for (int i = 0; i < n; i++)
if (arr[i] == ans)
return ans;
return -1;
}
// Driver Code
public static void main(String args[])
{
int arr[] = { 2, 2, 4 };
int n = arr.length;
System.out.println(findNumber(arr, n));
}
}
// This code is contributed by Nikita Tiwari
# Python3 program to find such number
# in the array that all array
# elements are divisible by it
# Returns GCD of two numbers
def gcd (a, b) :
if (a == 0) :
return b
return gcd (b % a, a)
# Function to return the desired
# number if exists
def findNumber (arr, n) :
# Find GCD of array
ans = arr[0]
for i in range(0, n) :
ans = gcd (ans, arr[i])
# Check if GCD is present in array
for i in range(0, n) :
if (arr[i] == ans) :
return ans
return -1
# Driver Code
arr = [2, 2, 4];
n = len(arr)
print(findNumber(arr, n))
# This code is contributed by Nikita Tiwari
<script>
// Javascript program to find such number in the array
// that all array elements are divisible by it
// Returns gcd of two numbers.
function gcd(a, b)
{
if (a == 0)
return b;
return gcd(b % a, a);
}
// Function to return the
// desired number if exists
function findNumber(arr, n)
{
// Find GCD of array
let ans = arr[0];
for (let i = 0; i < n; i++)
ans = gcd(ans, arr[i]);
// Check if GCD is present in array
for (let i = 0; i < n; i++)
if (arr[i] == ans)
return ans;
return -1;
}
let arr = [ 2, 2, 4 ];
let n = arr.length;
document.write(findNumber(arr, n));
</script>
// C# program to find such number in
// the array that all array elements
// are divisible by it
using System;
class GFG {
// Returns GCD of two numbers
static int gcd(int a, int b)
{
if (a == 0)
return b;
return gcd(b % a, a);
}
// Function to return the desired
// number if exists
static int findNumber(int[] arr, int n)
{
// Find GCD of array
int ans = arr[0];
for (int i = 0; i < n; i++)
ans = gcd(ans, arr[i]);
// Check if GCD is present in array
for (int i = 0; i < n; i++)
if (arr[i] == ans)
return ans;
return -1;
}
// Driver Code
public static void Main()
{
int[] arr = { 2, 2, 4 };
int n = arr.Length;
Console.WriteLine(findNumber(arr, n));
}
}
// This code is contributed by vt_m
<?php
// PHP program to find such
// number in the array that
// all array elements are
// divisible by it
// Returns gcd of two numbers
function gcd ($a, $b)
{
if ($a == 0)
return $b;
return gcd ($b % $a, $a);
}
// Function to return the
// desired number if exists
function findNumber ($arr, $n)
{
// Find GCD of array
$ans = $arr[0];
for ($i = 0; $i < $n; $i++)
$ans = gcd ($ans, $arr[$i]);
// Check if GCD is
// present in array
for ($i = 0; $i < $n; $i++)
if ($arr[$i] == $ans)
return $ans;
return -1;
}
// Driver Code
$arr =array (2, 2, 4);
$n = sizeof($arr);
echo findNumber($arr, $n), "\n";
// This code is contributed by ajit
?>
Time complexity: O(n*logn)
Auxiliary space: O(Amax), where Amax is the maximum element in the given array.
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