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Problem 100 | Project Euler | #102

Open sx349 opened 4 years ago

sx349 commented 4 years ago

https://pe-cn.github.io/100/

Problem 100 Arranged probability If a box contains twenty-one coloured discs, composed of fifteen blue discs and six red discs, and two discs were taken at random, it can be seen that the probability

yuandi42 commented 4 months ago

本质是个广义佩尔方程，但是如果穷举总数和蓝盘子数会发现其实这俩分别是 OEIS:A011900 , OEIS:A182435.

穷举有个快点的方式，就是设蓝盘子数 = (总数 / √2)向上取整。 这点在总数很大的时候很明显，但是在总数小于两位数的时候居然也是一样成立的。