55：丑数

丑数：因子只包含2,3,5的数，1为第一个丑数，2,3,5皆为丑数，请第1500个丑数。

public class Offer55 {

    public static void main(String[] args) {
        System.out.println(new Offer55().getUglyNumber_solution(5));
    }

    public int getUglyNumber_solution(int index){
        if(index<=0)return 0;
        int[] temp = new int[index];
        temp[0]=1;
        int towIndex = 0;
        int threeIndex = 0;
        int fiveIndex = 0;
        for(int i=1;i<index;i++){
            int min = Math.min(Math.min(temp[towIndex]*2,temp[threeIndex]*3),temp[fiveIndex]*5);
            temp[i] = min;
            if(temp[i] == temp[towIndex]*2)towIndex++;
            if(temp[i] == temp[threeIndex]*3)threeIndex++;
            if(temp[i] == temp[fiveIndex]*5)fiveIndex++;
        }

        return temp[index-1];
    }
}