Find element in array that divides all array elements
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
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.
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; } |
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Java
// 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 |
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Python3
# 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 |
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C#
// 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 |
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PHP
<?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 ?> |
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Output :
2
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