找到第1500个的丑数

package java_study.JianZhiOffer;

import org.junit.Test;

/**
 * Created by ethan on 2015/6/29.
 * 剑指offer No34找到第1500个的丑数（因数只有2,3,5三个数为丑数）
 * 空间换时间的做法
 */
public class No34找到丑数 {

    public int findUglyNumber(int x){
        int[] tmp = new int[x+1];
        tmp[1] = 1;
        int index_2 = 1;
        int index_3 = 1;
        int index_5 = 1;
        int count=2;
        while (count<=x){
            int min = getMin(tmp[index_2]*2, tmp[index_3]*3, tmp[index_5]*5);
            tmp[count++]=min;
            while (tmp[index_2]*2<=min)
                index_2++;
            while (tmp[index_3]*3<=min)
                index_3++;
            while (tmp[index_5]*5<=min)
                index_5++;
        }
        int ans = tmp[x];
        tmp = null;
        return ans;
    }
    public int getMin(int x, int y, int z){
        int tmp = x<y?x:y;
        return tmp<z?tmp:z;
    }

    @Test
    public void test1(){
        System.out.println(findUglyNumber(10));
    }
}