题解 | 丑数

#include <algorithm>
class Solution {
public:
    /**
     * 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
     */
    int GetUglyNumber_Solution(int index) {
        if(index == 0) return 0;
        vector<int> num2;
        vector<int> num3;
        vector<int> num5;
        int index2 = 0 ,index3 = 0, index5 = 0;
        int res = 1;
        for(int i = 1 ; i < index; i ++){
            num2.push_back(res *2) ;
            num3.push_back(res *3);
            num5.push_back(res *5);
            int min2 = num2[index2];
            int min3 = num3[index3];
            int min5 = num5[index5];
            int minNum = min (min(min2,min3),min5);
            if(minNum == min2) index2++;
            if(minNum == min3) index3++;
            if(minNum == min5) index5++;
            res = minNum;
        }
        return res;
    }
};