Most frequent factor in a range of integers

Difficulty Level : Basic
Last Updated : 22 Mar, 2021

You are given a range of numbers, from lower number to higher number (both inclusive). Consider all the factors of these numbers except 1, the task is to find the factor which appears the maximum number of times. If more than one number have maximum frequency than print anyone of them.
Examples:

Input : lower=10 higher=14
Output : The factor with maximum frequency is 2.

Input : lower=11 higher=11
Output : The factor with maximum frequency is 11.

Explanation:
If we have a range of numbers, say 10 to 14. Then the factors other than 1 will be:

10 => 2, 5, 10

11 => 11

12 => 2, 3, 4, 6, 12

13 => 13

14 => 2, 7, 14

In the above case, frequency(2)= 3, which is maximum on comparing with other factors.
Approach:
1. If lower = higher, then all factors will have frequency 1. So we can print any number which is factor, since every number is a factor of itself so we print the same number.
2. Otherwise, we print ‘2’ as it will always be true for a range of numbers.

C++

// CPP program to find most common factor
// in a range.
#include <bits/stdc++.h>
using namespace std;
 
int mostCommon(int lower, int higher)
{
    // Check whether lower number
    // and higher number are same
    if (lower == higher)
        return lower;
    else
        return 2;
}
 
// Driver Code
int main()
{
    int lower = 10; // Lower number
    int higher = 20; // Higher number
 
    printf("The most frequent factor %d\n",
               mostCommon(lower, higher));
    return 0;
}

Java

// Java program to find most common factor
// in a range.
 
public class GfG {
 
    public static int mostCommon(int lower, int higher)
    {
        // Check whether lower number 
        // and higher number are same
        if (lower == higher) 
            return lower;
        else
            return 2;
    }
 
    // Driver code
    public static void main(String []args) {
         
        int lower = 10; // Lower number
        int higher = 20; // Higher number
        System.out.println("The most frequent factor " +
                                    mostCommon(lower, higher));
    }
}
 
// This code is contributed by Rituraj Jain

Python 3

# Python 3 program to find most
# common factor in a range.
def mostCommon( lower, higher):
 
    # Check whether lower number
    # and higher number are same
    if (lower == higher):
        return lower
    else:
        return 2
 
# Driver Code
lower = 10 # Lower number
higher = 20 # Higher number
 
print("The most frequent factor",
       mostCommon(lower, higher))
 
# This code is contributed by ash264

C#

// C# program to find most common factor
// in a range.
using System;
 
class GFG
{
static int mostCommon(int lower, int higher)
{
    // Check whether lower number
    // and higher number are same
    if (lower == higher)
        return lower;
    else
        return 2;
}
 
// Driver Code
public static void Main()
{
    int lower = 10; // Lower number
    int higher = 20; // Higher number
 
    Console.WriteLine("The most frequent factor " +
                       mostCommon(lower, higher));
}
}
 
// This code is contributed
// by Akanksha Rai

PHP

<?php
// PHP program to find most common
// factor in a range.
 
function mostCommon($lower, $higher)
{
    // Check whether lower number
    // and higher number are same
    if ($lower == $higher)
        return $lower;
    else
        return 2;
}
 
// Driver Code
$lower = 10; // Lower number
$higher = 20; // Higher number
 
echo "The most frequent factor ".
    mostCommon($lower, $higher) . "\n";
 
// This code is contributed
// by Akanksha Rai
?>

Javascript

<script>
// javascript program to find most common factor
// in a range.
 
function mostCommon(lower , higher)
{
    // Check whether lower number 
    // and higher number are same
    if (lower == higher) 
        return lower;
    else
        return 2;
}
 
// Driver code
 
var lower = 10; // Lower number
var higher = 20; // Higher number
document.write("The most frequent factor " +
                            mostCommon(lower, higher));
 
// This code contributed by Princi Singh
</script>

Output:

The most frequent factor 2

Time Complexity: O(1)

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