> depending upon whether, when the strings are hanging straight down, all bars are separated by a positive distance no matter how they swing around on the string.
> 
> swing是什么概念？
> 比如输入样例，要是那个大bar很倾斜，然后string很短，然后小bar很水平，岂不是就撞上了？
不用考虑倾斜，只用判断天平平衡时棒与棒是否相交即可