Number of ways to divide a N elements equally into group of at least 2

Given an integer N denoting the number of elements, the task is to find the number of ways to divide these elements equally into groups such that each group has at least 2 elements.
Examples:
Input: N = 2
Output: 1
Explanation: There can be only one group.Input: N = 10
Output: 3
Explanation: There are 3 ways to divide elements:
One group having all the 10 elements.
Two groups where each group has 5 elements.
Five groups where each group has 2 elements.
Approach: The above problem can be solved using the below-given brute force approach. In every iteration of the loop, i represents the number of groups. If N is completely divisible by i, hence, the elements can be equally divided among groups. Follow the steps below to solve the problem:
- Declare variable ways and initialize it by 0.
- Iterate over the range [1, N/2] using the variable i and perform the following tasks:
- Check if N is completely divisible by i.
- If yes, then increment ways by 1.
- After performing the above steps, print the value of ways as the answer.
Below is the implementation of the above approach:
C++
// C++ program for the given approach#include <iostream>using namespace std;// Function to find the number of waysint numberofWays(int N){ // Variable to store the number of ways int ways = 0; int i; // Loop to find total number of ways for (i = 1; i <= N / 2; i++) { if (N % i == 0) ways++; } // Returning the number of ways return ways;}// Driver Codeint main(){ // Declaring and initialising N int N = 10; // Function call int ans = numberofWays(N); // Displaying the answer on screen cout << ans; return 0;} |
Java
// Java program for the above approachimport java.io.*;import java.lang.*;import java.util.*;class GFG { // Function to find the number of ways static int numberofWays(int N) { // Variable to store the number of ways int ways = 0; int i; // Loop to find total number of ways for (i = 1; i <= N / 2; i++) { if (N % i == 0) ways++; } // Returning the number of ways return ways; } public static void main (String[] args) { // Declaring and initialising N int N = 10; // Function call int ans = numberofWays(N); // Displaying the answer on screen System.out.print(ans); }}// This code is contributed by hrithikgarg03188 |
Python3
# Python code for the above approach # Function to find the number of waysdef numberofWays(N): # Variable to store the number of ways ways = 0; i = None # Loop to find total number of ways for i in range(1, (N // 2) + 1): if (N % i == 0): ways += 1 # Returning the number of ways return ways;# Driver Code# Declaring and initialising NN = 10;# Function callans = numberofWays(N);# Displaying the answer on screenprint(ans);# This code is contributed by Saurabh Jaiswal |
C#
// C# program for the above approachusing System;class GFG { // Function to find the number of ways static int numberofWays(int N) { // Variable to store the number of ways int ways = 0; int i; // Loop to find total number of ways for (i = 1; i <= N / 2; i++) { if (N % i == 0) ways++; } // Returning the number of ways return ways; } public static void Main(string[] args) { // Declaring and initialising N int N = 10; // Function call int ans = numberofWays(N); // Displaying the answer on screen Console.WriteLine(ans); }}// This code is contributed by ukasp. |
Javascript
<script> // JavaScript code for the above approach // Function to find the number of ways function numberofWays(N) { // Variable to store the number of ways let ways = 0; let i; // Loop to find total number of ways for (i = 1; i <= Math.floor(N / 2); i++) { if (N % i == 0) ways++; } // Returning the number of ways return ways; } // Driver Code // Declaring and initialising N let N = 10; // Function call let ans = numberofWays(N); // Displaying the answer on screen document.write(ans); // This code is contributed by Potta Lokesh </script> |
3
Time Complexity: O(N)
Auxiliary Space: O(1)
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