题解 | #丑数#

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param index int整型 
     * @return int整型
     */
    public int GetUglyNumber_Solution (int index) {
        // write code here
        int[] res = new int[index];
        if(index == 0) return 0;
        int i2 = 0, i3 = 0, i5 = 0;
        res[0] = 1;
        for(int i = 1; i < index; i ++){
            res[i] = Math.min(res[i2] * 2, Math.min(res[i3] * 3, res[i5]* 5));
            if(res[i] == res[i2] * 2) i2 ++;
            if(res[i] == res[i3] * 3) i3 ++;
            if(res[i] == res[i5] * 5) i5 ++;
        }
        return res[index - 1];
    }
}