单交叉
Single-Cross
题目详情
在标有 的平面上随机选择一条长度为 D 的线段 无限棋盘网格（即单位边长的方形网格）。 多长的 D 可以使线段交叉的概率最大化 棋盘网格上正好有一条线，这个最大值是多少 概率？
A random line segment of length D is chosen on a plane marked with an infinite checkerboard grid (i.e., a unit side length square grid). What length D maximizes the probability that the segment crosses exactly one line on the checkerboard grid, and what is this maximal probability?
解析
本月难题的答案是D = 1以及由此产生的 概率为2/（或约0.6366）。你们中的一些人能够 通过模拟确定这一点，其他人则进行了更具分析性的研究 方法。单击此处查看我们的解决方案文章。
恭喜我们所有的求解者！
Original Explanation
The answer to this month’s puzzle is that D = 1 and the resulting probability is 2/π (or about .6366). Some of you were able to determine this via simulation, and others went for a more analytical approach. Click here for our write-up of the solution.
Congratulations to all of our solvers!