Maximum positive integer divisible by C and is in the range [A, B]

Given three positive integers A, B and C. The task is to find the maximum integer X > 0 such that:

  1. X % C = 0 and
  2. X must belong to the range [A, B]

Print -1 if no such number i.e. X exists.

Examples:



Input: A = 2, B = 4, C = 2
Output: 4
B is itself divisible by C.

Input: A = 5, B = 10, C = 4
Output: 8 
B is not divisble by C. 
So maximum multiple of 4(C) smaller than 10(B) is 8

Approach:

  • If B is a multiple of C then B is the required number.
  • Else get the maximum multiple of C just lesser than B which is the required answer.

Below is the implementation of the above approach:

C++

filter_none

edit
close

play_arrow

link
brightness_4
code

// C++ implementation of the above approach
#include <iostream>
using namespace std;
  
// Function to return the required number
int getMaxNum(int a, int b, int c)
{
  
    // If b % c = 0 then b is the
    // required number
    if (b % c == 0)
        return b;
  
    // Else get the maximum multiple of
    // c smaller than b
    int x = ((b / c) * c);
      
    if (x >= a && x <= b)
        return x;
    else 
        return -1;
}
  
// Driver code
int main()
{
    int a = 2, b = 10, c = 3;
    cout << getMaxNum(a, b, c);
    return 0;
}

chevron_right


Java

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java implementation of the above approach
import java.io.*;
  
class GFG 
{
      
// Function to return the required number
static int getMaxNum(int a, int b, int c)
{
  
    // If b % c = 0 then b is the
    // required number
    if (b % c == 0)
        return b;
  
    // Else get the maximum multiple of
    // c smaller than b
    int x = ((b / c) * c);
      
    if (x >= a && x <= b)
        return x;
    else
        return -1;
}
  
// Driver code
public static void main (String[] args) 
{
    int a = 2, b = 10, c = 3;
    System.out.println(getMaxNum(a, b, c));
}
}
  
// This Code is contributed by ajit.. 

chevron_right


Python3

filter_none

edit
close

play_arrow

link
brightness_4
code

# Python3 implementation of the above approach
  
# Function to return the required number
def getMaxNum(a, b, c):
  
    # If b % c = 0 then b is the
    # required number
    if (b % c == 0):
        return b
  
    # Else get the maximum multiple 
    # of c smaller than b
    x = ((b //c) * c)
      
    if (x >= a and x <= b):
        return x
    else:
        return -1
  
# Driver code
a, b, c = 2, 10, 3
print(getMaxNum(a, b, c))
  
# This code is contributed 
# by Mohit Kumar

chevron_right


C#

filter_none

edit
close

play_arrow

link
brightness_4
code

// C# implementation of the above approach
using System;
class GFG 
{
      
// Function to return the required number
static int getMaxNum(int a, int b, int c)
{
  
    // If b % c = 0 then b is the
    // required number
    if (b % c == 0)
        return b;
  
    // Else get the maximum multiple of
    // c smaller than b
    int x = ((b / c) * c);
      
    if (x >= a && x <= b)
        return x;
    else
        return -1;
}
  
// Driver code
public static void Main () 
{
    int a = 2, b = 10, c = 3;
    Console.WriteLine(getMaxNum(a, b, c));
}
}
  
// This Code is contributed by Code_Mech.. 

chevron_right


PHP

filter_none

edit
close

play_arrow

link
brightness_4
code

<?php
// PHP implementation of the above approach
// Function to return the required number
function getMaxNum($a, $b, $c)
{
  
    // If b % c = 0 then b is the
    // required number
    if ($b % $c == 0)
        return $b;
  
    // Else get the maximum multiple
    // of c smaller than b
    $x = ((int)($b / $c) * $c);
      
    if ($x >= $a && $x <= $b)
        return $x;
    else
        return -1;
}
  
// Driver code
$a = 2; $b = 10; $c = 3;
echo(getMaxNum($a, $b, $c));
  
// This Code is contributed
// by Mukul Singh
?>

chevron_right


Output:

9


My Personal Notes arrow_drop_up

Discovering ways to develop a plane for soaring career goals

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.





Article Tags :
Practice Tags :


Be the First to upvote.


Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.