27E_Number_With_The_Given_Amount_Of_Divisors | C# Online Compiler

27E_Number_With_The_Given_Amount_Of_Divisors by kartoxa

using System;
using System.Collections.Generic;
					
public class Program
{
	public static void Main()
	{
		int n = int.Parse(Console.ReadLine());
		
		if(n == 1)
		{
			Console.WriteLine(1);
			return;
		}
		
		int prime = 2;
		int current = n;
		var primes = new Dictionary<int, int>();
		int usedPrimes = 0;
			
		while(true)
		{		
			if(current % prime == 0)
			{
				current /= prime;
				
				if(!primes.ContainsKey(prime))
				{
					primes.Add(prime, 0);
					usedPrimes++;
				}
				
				primes[prime]++;
				
				if(current == 1)
				{
					break;
				}
			}
			else
			{
				prime = FindNextPrime(prime);
			}
		}
		
		long powersOfTwo = - 1;
		if(n <= 60)
		{
			powersOfTwo = (long)Math.Pow(2, n - 1);
		}
		
		long factorized = 1;
		if(usedPrimes > 1)
		{
			foreach(var pair in primes)
			{
				factorized *= (long)Math.Pow(pair.Key, pair.Value);
			}
			
			factorized /= 2;
		}
		
		if(usedPrimes == 1 && n <= 60)
		{
			Console.WriteLine(powersOfTwo);
		}
		else if(n <= 60)
		{
			Console.WriteLine(Math.Min(powersOfTwo, factorized));
		}
		else
		{
			Console.WriteLine(factorized);
		}
	}
	
	public static int FindNextPrime(int prime)
	{
		if(prime == 2)
		{
			return 3;
		}
		else
		{
			int num = prime + 2;
			
			while(true)
			{
				bool isPrime = true;
				
				for(int i = 3; i <= num / 2; i += 2)
				{
					if(num % i == 0)
					{
						isPrime = false;
						break;
					}
				}
				
				if(isPrime)
				{
					return num;
				}
			}
		}
	}
}

 
using System;
using System.Collections.Generic;
                    
public class Program
{
    public static void Main()
    {
        int n = int.Parse(Console.ReadLine());
        
        if(n == 1)
        {
            Console.WriteLine(1);
            return;
        }
        
        int prime = 2;
        int current = n;
        var primes = new Dictionary<int, int>();
        int usedPrimes = 0;
            
        while(true)
        {       
            if(current % prime == 0)
            {
                current /= prime;
                
                if(!primes.ContainsKey(prime))
                {
                    primes.Add(prime, 0);
                    usedPrimes++;
                }
                
                primes[prime]++;
                
                if(current == 1)
                {
                    break;
                }
            }
            else
            {
                prime = FindNextPrime(prime);
            }
        }
        
        long powersOfTwo = - 1;
        if(n <= 60)
        {
            powersOfTwo = (long)Math.Pow(2, n - 1);
        }
        
        long factorized = 1;
        if(usedPrimes > 1)
        {
            foreach(var pair in primes)
            {
                factorized *= (long)Math.Pow(pair.Key, pair.Value);
            }
            
            factorized /= 2;
        }
        
        if(usedPrimes == 1 && n <= 60)
        {
            Console.WriteLine(powersOfTwo);
        }
        else if(n <= 60)
        {
            Console.WriteLine(Math.Min(powersOfTwo, factorized));
        }
        else
        {
            Console.WriteLine(factorized);
        }
    }
    
    public static int FindNextPrime(int prime)
    {
        if(prime == 2)
        {
            return 3;
        }
        else
        {
            int num = prime + 2;
            
            while(true)
            {
                bool isPrime = true;
                
                for(int i = 3; i <= num / 2; i += 2)
                {
                    if(num % i == 0)
                    {
                        isPrime = false;
                        break;
                    }
                }
                
                if(isPrime)
                {
                    return num;
                }
            }
        }
    }
}

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