牛客编程巅峰赛S1第8场 - 青铜&白银 翻滚吧牛牛(一)

class Solution {
public:
    /**
     *
     * @param k int整型 翻滚次数
     * @return double浮点型
     */
    double circumference(int k) {
        // write code here
        double pi = 3.1415926535898;
        double s[] = { pi / 3.0, sqrt(3.0) * pi / 3.0, 2.0 * pi / 3.0, sqrt(3.0) * pi / 3.0, pi / 3.0,0.0 };

        double r = 0;
        for (int i = 1;i <= k;i++)
        {
            r += s[(i - 1) % 6];
        }
        return r;
    }
};