题目

ugly-number-ii

2. 算法

* 直接模拟

3. 代码

class Solution {

public:

    int nthUglyNumber(int n) {

        vector<int> res(1, 1);

        int i2 = 0, i3 = 0, i5 = 0;

        while (res.size() < n) {

            int m2 = res[i2] * 2, m3 = res[i3] * 3, m5 = res[i5] * 5;

            int mn = min(m2, min(m3, m5));

            if (mn == m2) ++i2;

            if (mn == m3) ++i3;

            if (mn == m5) ++i5;

            res.push_back(mn);

        }

        return res.back();

    }

};