编程介的小学生 2017-10-31 04:29 采纳率: 20.5%
浏览 813
已采纳

Equilibrium Mobile

Problem Description

A mobile is a type of kinetic sculpture constructed to take advantage of the principle of equilibrium. It consists of a number of rods, from which weighted objects or further rods hang. The objects hanging from the rods balance each other, so that the rods remain more or less horizontal. Each rod hangs from only one string, which gives it freedom to rotate about the string.

We consider mobiles where each rod is attached to its string exactly in the middle, as in the figure underneath. You are given such a configuration, but the weights on the ends are chosen incorrectly, so that the mobile is not in equilibrium. Since that's not aesthetically pleasing, you decide to change some of the weights.

What is the minimum number of weights that you must change in order to bring the mobile to equilibrium? You may substitute any weight by any (possibly non-integer) weight. For the mobile shown in the figure, equilibrium can be reached by changing the middle weight from 7 to 3, so only 1 weight needs to changed.

Input
On the first line one positive number: the number of testcases, at most 100. After that per testcase:

  • One line with the structure of the mobile, which is a recursively defined expression of the form:

::= | "[" "," "]"

with a positive integer smaller than 109 indicating a weight and [,] indicating a rod with the two expressions at the ends of the rod. The total number of rods in the chain from a weight to the top of the mobile will be at most 16.

Output
Per testcase:

  • One line with the minimum number of weights that have to be changed.

Sample Input
3
[[3,7],6]
40
[[2,3],[4,5]]

Sample Output
1
0
3

  • 写回答

1条回答 默认 最新

  • threenewbee 2017-11-23 15:55
    关注
    本回答被题主选为最佳回答 , 对您是否有帮助呢?
    评论

报告相同问题?

悬赏问题

  • ¥15 微信会员卡接入微信支付商户号收款
  • ¥15 如何获取烟草零售终端数据
  • ¥15 数学建模招标中位数问题
  • ¥15 phython路径名过长报错 不知道什么问题
  • ¥15 深度学习中模型转换该怎么实现
  • ¥15 HLs设计手写数字识别程序编译通不过
  • ¥15 Stata外部命令安装问题求帮助!
  • ¥15 从键盘随机输入A-H中的一串字符串,用七段数码管方法进行绘制。提交代码及运行截图。
  • ¥15 TYPCE母转母,插入认方向
  • ¥15 如何用python向钉钉机器人发送可以放大的图片?