题目描述
把只包含质因子2、3和5的数称作丑数(Ugly Number)。例如6、8都是丑数,但14不是,因为它包含质因子7。 习惯上我们把1当做是第一个丑数。求按从小到大的顺序的第N个丑数
class Solution { public: int GetUglyNumber_Solution(int index) { if(index<7) return index; vector<int> arr; int nowmin = 1; arr.push_back(nowmin); int p2 = 0; int p3 = 0; int p5 = 0; while(arr.size()<index) { nowmin = min(arr[p2]*2, min(arr[p3]*3, arr[p5]*5)); if(nowmin==arr[p2]*2) p2++; if(nowmin==arr[p3]*3) p3++; if(nowmin==arr[p5]*5) p5++; arr.push_back(nowmin); } return nowmin; } };
参考博客:https://blog.csdn.net/Fly_as_tadpole/article/details/82705774
感觉这个题好难,特别不容易理解,还得多看几遍。。。。