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thousandlemons/result.json

Last active January 4, 2017 12:12
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  1. Nathaniel Sun renamed this gist Jan 4, 2017. 1 changed file with 0 additions and 0 deletions.
    0 description.md → the-light-bulb-problem.md
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  2. Nathaniel Sun revised this gist Nov 1, 2016. 1 changed file with 2 additions and 0 deletions.
    2 changes: 2 additions & 0 deletions description.md
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    # The Light Bulb Problem

    There are 150 light bulbs each with a flip switch, indexed from 1 to 150. Initially, they are all on.

    First, you look at each of the light bulbs sequentially, and flip the switch if its index number is divisible by 3.
  3. Nathaniel Sun revised this gist Nov 1, 2016. No changes.
  4. Nathaniel Sun renamed this gist Nov 1, 2016. 1 changed file with 0 additions and 0 deletions.
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  5. Nathaniel Sun created this gist Nov 1, 2016.
    7 changes: 7 additions & 0 deletions description.txt
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    There are 150 light bulbs each with a flip switch, indexed from 1 to 150. Initially, they are all on.

    First, you look at each of the light bulbs sequentially, and flip the switch if its index number is divisible by 3.

    Then, you iterate through all the light bulbs again, but this time you only flip the switch if the index number is divisible by 5.

    How many light bulbs are on now?
    5 changes: 5 additions & 0 deletions result.json
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    {
    "off": 60,
    "on": 90,
    "size": 150
    }
    59 changes: 59 additions & 0 deletions solution.py
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    import json


    class LightBulb(object):
    on = None

    def __init__(self, on=False):
    self.on = on

    def turn_on(self):
    self.on = True

    def turn_off(self):
    self.on = False

    def flip_switch(self):
    self.on = not self.on


    class Bus(object):
    light_bulbs = []

    def __init__(self, size):
    for i in range(size):
    self.light_bulbs.append(LightBulb(on=True))

    def analyze(self):
    on_count = 0
    off_count = 0
    for lb in self.light_bulbs:
    if lb.on:
    on_count += 1
    else:
    off_count += 1

    return {
    'size': len(self.light_bulbs),
    'on': on_count,
    'off': off_count
    }

    def flip_if_index_is_a_multiple_of(self, divisor):
    for index, light_bulb in enumerate(self.light_bulbs):
    human_readable_index = index + 1
    if human_readable_index % divisor == 0:
    light_bulb.flip_switch()


    def main():
    bus = Bus(size=150)
    bus.flip_if_index_is_a_multiple_of(divisor=3)
    bus.flip_if_index_is_a_multiple_of(divisor=5)
    analysis = bus.analyze()
    with open('result.json', 'w+') as file:
    file.write(json.dumps(analysis, indent=4, sort_keys=True))


    if __name__ == '__main__':
    main()