eulers

gistfile1.txt

package edu.wpi.tmathmeyer.euler;

public class Probs {
	public static void problem30(){
		int[] fives = new int[10];
		for(int i = 0; i < 10; i++)
		{
			fives[i] = pow(i, 5);
			System.out.println(fives[i]);
		}
		int sup = 0;
		for(int i = 2; i < 999999; i++)
		{
			int sum = 0;
			for(int j = 0; j < (i+"").length(); j++)
			{
				int digit = Integer.parseInt((i+"").charAt(j)+"");
				sum += fives[digit];
				if (sum > i)
				{
					j = 1324098;
				}
			}
			if (sum == i && i != 59049)
			{
				System.out.println("answer: "+sum);
				sup+=sum;
				
			}
			if (i%1000 == 0)
			{
				//System.out.println(i/1000 + "%");
			}
		}
		System.out.println(sup);
	}
	
	public static int pow(int a, int b)
	{ // a^b
		if (b==0)
		{
			return 1;
		}
		if (b==1)
		{
			return a;
		}
		if (b%2 == 0)
		{
			return pow(a*a, b/2);
		}
		return a * pow (a, b-1);
	}
	
	
	
	public static void problem33()
	{
		for (int num = 1; num < 100; num++)
		{
			for(int dem = num+1; dem < 100; dem++)
			{
				if ((num%10 == dem/10) && (dem%10 * num == (num/10) * dem)){
					System.out.println(num+"/"+dem);
				}
			}
		}
	}
	
	
	public static void problem37()
	{
		int[] i = new int[100000];
		for(int x = 2; x < 100000; x++)
		{
			if (i[x] == 0)
			{
				for(int k = 2*x; k < 100000; k += x)
				{
					i[k] = 1;
				}
				if (!(x%10==7 || x%10==3))
				{
					i[x] = 1;
				}
				else
				{
					int q = pow(10, (x+"").length()-1);
					if (!(x/q==7 || x/q==3))
					{
						i[x] = 1;
					}
				}
			}
		}
		for(int x = 1; x < 1000; x++)
		{
			System.out.print(i[x]==0?x+"\n":"");
		}
		
	}
	
	
	public static void main(String[] args){
		problem37();
	}
}