CareerCup

Other solutions are similar, but this uses a technique I discovered today to track the level as we perform the BFT. As level increments, we can calculate exponential of 4% more accurately.

interface Member {     
	public double getMonthlyAmazonDollars();
	public Collection<Member> getRecruitedMembers(); 
}

class MemberPayoutUtil implements Member {
	private MemberPayoutUtil[] children;
	public MemberPayoutUtil(MemberPayoutUtil[] children) {
		this.children = children;
	}
	public int getNumChildren () {
		return children.length;
	}
	public MemberPayoutUtil getChild(int index) {
		return children[index];
	}

	public double getMonthlyAmazonDollars() {
		return 10000.00;
	}
	//returns breadth-first traversal of recruited members in collection
	public Collection<Member> getRecruitedMembers() {
		Collection<Member> collection = new LinkedList<Member>();
		Queue<MemberPayoutUtil> queue = new LinkedList<MemberPayoutUtil>();
		queue.add(this);
		int levelCounter = 0;
		int level = 0;
		while(!queue.isEmpty()) {
			MemberPayoutUtil node = queue.remove();
			collection.add(node);
			for (int i = 0; i < node.getNumChildren(); i++ ) {
				queue.add( node.getChild(i) );
			}
		}
		return collection;
	}
	
		//as percentage of getMonthlyAmazonDollars
	public double calculatePayout() {
		double payout = 0;
		Queue<MemberPayoutUtil> queue = new LinkedList<MemberPayoutUtil>();
		queue.add(this);
		int levelCounter = 0;
		int level = 0;
		while(!queue.isEmpty()) {
			MemberPayoutUtil node = queue.remove();
			//could print name or id here.
			payout += .1 * getMonthlyAmazonDollars();
			for (int i = 0; i < node.getNumChildren(); i++ ) {
				queue.add( node.getChild(i) );
			}
			if( levelCounter==0 ) {
				levelCounter=queue.size();
				level++;
				payout += Math.pow(.04, level) * getMonthlyAmazonDollars();
			}
			levelCounter--;
		}
		return payout;
	}
}