Given a positive integer N, the task is to generate an array such that the sum of the Euler Totient Function of each element is equal to N.
Examples:
Input: N = 6
Output: 1 6 2 3Input: N = 12
Output: 1 12 2 6 3 4
Approach: The given problem can be solved based on the divisor sum property of the Euler Totient Function, i.e.,
- The Euler Totient Function of a number N< is the number of integers from 1 to N that gives GCD(i, N) as 1 and a number N can be represented as the summation of the Euler Totient Function values of all the divisors of N.
- Therefore, the idea is to find the divisors of the given number N as the resultant array.
Below is the implementation of the above approach:
C++
// C++ program for the above approach #include <bits/stdc++.h> using namespace std; // Function to construct the array such // the sum of values of Euler Totient // functions of all array elements is N void constructArray( int N) { // Stores the resultant array vector< int > ans; // Find divisors in sqrt(N) for ( int i = 1; i * i <= N; i++) { // If N is divisible by i if (N % i == 0) { // Push the current divisor ans.push_back(i); // If N is not a // perfect square if (N != (i * i)) { // Push the second divisor ans.push_back(N / i); } } } // Print the resultant array for ( auto it : ans) { cout << it << " " ; } } // Driver Code int main() { int N = 12; // Function Call constructArray(N); return 0; } |
Java
// Java program for the above approach import java.util.*; class GFG{ // Function to construct the array such // the sum of values of Euler Totient // functions of all array elements is N static void constructArray( int N) { // Stores the resultant array ArrayList<Integer> ans = new ArrayList<Integer>(); // Find divisors in sqrt(N) for ( int i = 1 ; i * i <= N; i++) { // If N is divisible by i if (N % i == 0 ) { // Push the current divisor ans.add(i); // If N is not a // perfect square if (N != (i * i)) { // Push the second divisor ans.add(N / i); } } } // Print the resultant array for ( int it : ans) { System.out.print(it + " " ); } } // Driver Code public static void main(String[] args) { int N = 12 ; // Function Call constructArray(N); } } // This code is contributed by splevel62 |
Python3
# Python3 program for the above approach from math import sqrt # Function to construct the array such # the sum of values of Euler Totient # functions of all array elements is N def constructArray(N): # Stores the resultant array ans = [] # Find divisors in sqrt(N) for i in range ( 1 , int (sqrt(N)) + 1 , 1 ): # If N is divisible by i if (N % i = = 0 ): # Push the current divisor ans.append(i) # If N is not a # perfect square if (N ! = (i * i)): # Push the second divisor ans.append(N / i) # Print the resultant array for it in ans: print ( int (it), end = " " ) # Driver Code if __name__ = = '__main__' : N = 12 # Function Call constructArray(N) # This code is contributed by ipg2016107 |
C#
// C# program for the above approach using System; using System.Collections.Generic; class GFG{ // Function to construct the array such // the sum of values of Euler Totient // functions of all array elements is N static void constructArray( int N) { // Stores the resultant array List< int > ans = new List< int >(); // Find divisors in sqrt(N) for ( int i = 1; i * i <= N; i++) { // If N is divisible by i if (N % i == 0) { // Push the current divisor ans.Add(i); // If N is not a // perfect square if (N != (i * i)) { // Push the second divisor ans.Add(N / i); } } } // Print the resultant array foreach ( int it in ans) { Console.Write(it + " " ); } } // Driver Code public static void Main() { int N = 12; // Function Call constructArray(N); } } // This code is contributed by ukasp |
Javascript
<script> // javascript program for the above approach // Function to construct the array such // the sum of values of Euler Totient // functions of all array elements is N function constructArray(N) { // Stores the resultant array var ans = []; // Find divisors in sqrt(N) for ( var i = 1; i * i <= N; i++) { // If N is divisible by i if (N % i == 0) { // Push the current divisor ans.push(i); // If N is not a // perfect square if (N != (i * i)) { // Push the second divisor ans.push(N / i); } } } // Print the resultant array document.write(ans); } // Driver Code var N = 12; // Function Call constructArray(N); // This code contributed by shikhasingrajput </script> |
Output:
1 12 2 6 3 4
Time Complexity: O(√N)
Auxiliary Space: O(N)
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