Longest sub-sequence with minimum LCM

Given an array arr[] of length N, the task is to find the length of the longest sub-sequence with minimum possible LCM.

Examples:

Input: arr[] = {1, 3, 1}
Output: 2
{1} and {1} are the subsequences
with the minimum possible LCM.



Input: arr[] = {3, 4, 5, 3, 2, 3}
Output: 1
{2} is the required subsequence.

Approach: The minimum possible LCM from the array will be equal to the value of the smallest element in the array. Now, to maximize the length of the resulting subsequence, find the number of elements with a value equal to this smallest value in the array and the count of these elements 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 approach
#include <bits/stdc++.h>
using namespace std;
  
// Function to return the length
// of the largest subsequence with
// minimum possible LCM
int maxLen(int* arr, int n)
{
    // Minimum value from the array
    int min_val = *min_element(arr, arr + n);
  
    // To store the frequency of the
    // minimum element in the array
    int freq = 0;
  
    for (int i = 0; i < n; i++) {
  
        // If current element is equal
        // to the minimum element
        if (arr[i] == min_val)
            freq++;
    }
  
    return freq;
}
  
// Driver code
int main()
{
    int arr[] = { 1, 3, 1 };
    int n = sizeof(arr) / sizeof(int);
  
    cout << maxLen(arr, n);
  
    return 0;
}

chevron_right


Java

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java implementation of the approach
import java.util.Arrays;
  
class GFG 
{
  
// Function to return the length
// of the largest subsequence with
// minimum possible LCM
static int maxLen(int[] arr, int n)
{
    // Minimum value from the array
    int min_val = Arrays.stream(arr).min().getAsInt();
  
    // To store the frequency of the
    // minimum element in the array
    int freq = 0;
  
    for (int i = 0; i < n; i++) 
    {
  
        // If current element is equal
        // to the minimum element
        if (arr[i] == min_val)
            freq++;
    }
  
    return freq;
}
  
// Driver code
public static void main(String []args)
{
    int arr[] = { 1, 3, 1 };
    int n = arr.length;
  
    System.out.println(maxLen(arr, n));
}
}
  
// This code is contributed by PrinciRaj1992

chevron_right


Python3

filter_none

edit
close

play_arrow

link
brightness_4
code

# Python3 implementation of the approach
  
# Function to return the length 
# of the largest subsequence with 
# minimum possible LCM 
def maxLen(arr, n) :
  
    # Minimum value from the array 
    min_val = min(arr); 
  
    # To store the frequency of the 
    # minimum element in the array 
    freq = 0
  
    for i in range(n) :
  
        # If current element is equal 
        # to the minimum element 
        if (arr[i] == min_val) :
            freq += 1;
  
    return freq; 
  
# Driver code 
if __name__ == "__main__"
  
    arr = [ 1, 3, 1 ]; 
      
    n = len(arr); 
  
    print(maxLen(arr, n)); 
  
# This code is contributed by AnkitRai01

chevron_right


C#

filter_none

edit
close

play_arrow

link
brightness_4
code

// C# implementation of the approach
using System;
using System.Linq;
      
class GFG 
{
  
// Function to return the length
// of the largest subsequence with
// minimum possible LCM
static int maxLen(int[] arr, int n)
{
    // Minimum value from the array
    int min_val = arr.Min();
  
    // To store the frequency of the
    // minimum element in the array
    int freq = 0;
  
    for (int i = 0; i < n; i++) 
    {
  
        // If current element is equal
        // to the minimum element
        if (arr[i] == min_val)
            freq++;
    }
  
    return freq;
}
  
// Driver code
public static void Main(String []args)
{
    int []arr = { 1, 3, 1 };
    int n = arr.Length;
  
    Console.WriteLine(maxLen(arr, n));
}
}
  
// This code is contributed by 29AjayKumar

chevron_right


Output:

2


My Personal Notes arrow_drop_up

Check out this Author's contributed articles.

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.