Solution29.java

//Problem 29 - Project Euler

/*
GOAL:
Find # of distinct terms in the sequence generated by a^b for 2 ≤ a ≤ 100 and 2 ≤ b ≤ 100
LOGIC:
STEP1:
1st Loop to get base (a) abd 2nd Loop to calculate powers from 2 to 100 (b)
STEP2:
Convert the BigIntger Powers to string and stroe in an array
STEP3:
Pass the string array to an Hashset, get its size - 1, as null is not counted
*/

import java.io.*;
import java.util.*;
import java.math.BigInteger;

public class Solution29 {
	
    public static void main(String[] args) {
    	String[] big_hold = new String[10000];
        int id = 0;
    	BigInteger start = BigInteger.ONE;
    	String store_temp;
        //get base
    	for(int i=2; i<=5; i++){
    		store_temp = Integer.toString(i);
    		BigInteger big = new BigInteger(store_temp);
            //find all powers from 2 to 100
    		for (int j=2; j<=5; j++) {
                start = big.pow(j);
                store_temp = start.toString();
                System.out.println(store_temp);
                big_hold[id] = store_temp;
                id++;
            }
    	}
        //A collection that contains no duplicate elements. 
        //More formally, sets contain no pair of elements e1 and e2 such that e1.equals(e2), and at most one null element.
        Set<String> refined_string = new HashSet<String>(Arrays.asList(big_hold));
        int size = refined_string.size();
        System.out.println(refined_string);//1st element is null
        System.out.println(size);
    }

}

//ANSWER: 9183