Question.java

package Question10_7;

import java.util.Queue;
import java.util.LinkedList;

public class Question {

	public static int getKthMagicNumber(int k) {
		if (k <= 0) return 0;
		int val = 1;
		Queue<Integer> Q3 = new LinkedList<Integer>();
		Queue<Integer> Q5 = new LinkedList<Integer>();
		Queue<Integer> Q7 = new LinkedList<Integer>();
		Q3.add(3);
		Q5.add(5);
		Q7.add(7);
		for (--k; k > 0; --k) { // We�ve done one iteration already.
			val = Math.min(Q3.peek().intValue(), Math.min(Q5.peek().intValue(), Q7.peek().intValue()));
			if (val == Q7.peek()) {
				Q7.remove();
			} else {
				if (val == Q5.peek()) {
					Q5.remove();
				} else { // must be from Q3
					Q3.remove();
					Q3.add(val * 3);
				}
				Q5.add(val * 5);
			}
			Q7.add(val * 7);
		}
		return val;
	}
	
	public static void main(String[] args) {
		for (int i = 0; i < 14; i++) {
			System.out.println(i + " : " + getKthMagicNumber(i));
		}
	}
}