ruby-on-rails - Fare calculator for any entity

Question

I'm working on creating a booking fare calculator.

There are 28 bus stations,

Base Price is 100 up to 5 bus stations.

Later 50 extra for every 5 bus stations.

Single trip from 1 to 28 is 300.

Here is my solution,

BASE = 100
stops = (start - end).abs

case stops
when 1..5
  BASE
when 5..10
  BASE + 5
when 10..15
  BASE + 10
when 15..16
  BASE + 15
when (station_array.length - 1)..station_array.length
  200
end

I was looking for a good optimised and scalable solution. Suppose if, we add new stations, the fare logic should require minimal changes.

标签： ruby-on-railsruby

Answer 1

您应该能够只用基本的数学来做到这一点，这可以作为您构建的示例。

以后每 5 个公交车站加收 50 元。

这有点不清楚，是在5个额外站之后计算的额外票价还是已经在第一个额外的？

例如是吗？

A: 6 stations = BASE_FARE + EXTRA_FARE
# or...
B: 6 stations = BASE_FARE only

ceil如果您只想计算5个站后的额外票价，您可以删除该方法，我这里的方法是1-4个额外的车站已经添加了额外的票价。

至于往返，您可以添加一个额外的检查来查看站数 = total_stations

TOTAL_STATIONS = 500
ROUNDFARE = 300 # or whatever

BASE_PRICE = 100
BASE_STATIONS = 5

EXTRA_PRICE = 50
EXTRA_STATIONS = 5

def calc_price(stations)
  return ROUNDFARE if stations = TOTAL_STATIONS
  total_price = base_price

  # Substract the 5 base stations
  stations -= BASE_STATIONS

  # Add 50 for every 5 stations
  # to_f is used so it does float division
  # ceil is used to round up, e.g. 3 / 5 => 1
  total_price += (stops / EXTRA_STATIONS.to_f).ceil * EXTRA_PRICE

  total_price
end