開発環境
- macOS Mojave - Apple (OS)
- Emacs (Text Editor)
- Windows 10 Pro (OS)
- Visual Studio Code (Text Editor)
- Python 3.7 (プログラミング言語)
問題解決のPythonプログラミング ―数学パズルで鍛えるアルゴリズム的思考 (Srini Devadas (著)、黒川 利明 (翻訳)、オライリージャパン)の5章(水晶をどうぞ壊してください)、練習問題(問題3)を取り組んでみる。
コード(Emacs)
Python 3
#!/usr/bin/env python3
def convert_to_decimal(r, d, rep):
return sum([rep[i] * r ** (d - (i + 1)) for i in range(d)])
def how_hard_is_the_crystal(n, d, did_break=None):
r = 1
while r ** d <= n:
r += 1
print(f'Radix chosen is {r}')
ball_number = 1
num_drops = 0
floor_no_break = [0] * d
lower = 0
upper = n
for i in range(d):
for j in range(r - 1):
floor_no_break[i] += 1
floor = convert_to_decimal(r, d, floor_no_break)
if floor > n:
floor_no_break[i] -= 1
break
print(f'Interval: [{lower}, {upper}]')
print(f'Broken balls: {ball_number - 1}')
print(f'Drop ball {ball_number} from floor {floor}')
# did_break = input('Did the ball break (yes/no)?: ')
print(f'Did the ball break?: {did_break[i]}')
num_drops += 1
# if did_break == 'yes':
if did_break[i] == 'yes':
upper = floor - 1
floor_no_break[i] -= 1
ball_number += 1
break
lower = floor
print(f'Interval: [{lower}, {upper}]')
hardness = convert_to_decimal(r, d, floor_no_break)
return hardness, num_drops
if __name__ == '__main__':
def yes_no(n):
if n % 2 == 0:
return 'yes'
return 'no'
for did_break in [['no'] * 6,
['yes'] * 6,
[yes_no(i) for i in range(6)],
[yes_no(i + 1) for i in range(6)]]:
print(how_hard_is_the_crystal(128, 6, did_break))
print()
入出力結果(Terminal, Jupyter(IPython))
$ ./sample3.py Radix chosen is 3 Interval: [0, 128] Broken balls: 0 Drop ball 1 from floor 81 Did the ball break?: no Interval: [81, 128] Broken balls: 0 Drop ball 1 from floor 108 Did the ball break?: no Interval: [108, 128] Broken balls: 0 Drop ball 1 from floor 117 Did the ball break?: no Interval: [117, 128] Broken balls: 0 Drop ball 1 from floor 126 Did the ball break?: no Interval: [126, 128] Broken balls: 0 Drop ball 1 from floor 127 Did the ball break?: no Interval: [127, 128] Broken balls: 0 Drop ball 1 from floor 128 Did the ball break?: no Interval: [128, 128] (128, 6) Radix chosen is 3 Interval: [0, 128] Broken balls: 0 Drop ball 1 from floor 81 Did the ball break?: yes Interval: [0, 80] Broken balls: 1 Drop ball 2 from floor 27 Did the ball break?: yes Interval: [0, 26] Broken balls: 2 Drop ball 3 from floor 9 Did the ball break?: yes Interval: [0, 8] Broken balls: 3 Drop ball 4 from floor 3 Did the ball break?: yes Interval: [0, 2] Broken balls: 4 Drop ball 5 from floor 1 Did the ball break?: yes Interval: [0, 0] (0, 5) Radix chosen is 3 Interval: [0, 128] Broken balls: 0 Drop ball 1 from floor 81 Did the ball break?: no Interval: [81, 128] Broken balls: 0 Drop ball 1 from floor 108 Did the ball break?: yes Interval: [81, 107] Broken balls: 1 Drop ball 2 from floor 90 Did the ball break?: no Interval: [90, 107] Broken balls: 1 Drop ball 2 from floor 99 Did the ball break?: no Interval: [99, 107] Broken balls: 1 Drop ball 2 from floor 102 Did the ball break?: yes Interval: [99, 101] Broken balls: 2 Drop ball 3 from floor 100 Did the ball break?: no Interval: [100, 101] Broken balls: 2 Drop ball 3 from floor 101 Did the ball break?: no Interval: [101, 101] (101, 7) Radix chosen is 3 Interval: [0, 128] Broken balls: 0 Drop ball 1 from floor 81 Did the ball break?: yes Interval: [0, 80] Broken balls: 1 Drop ball 2 from floor 27 Did the ball break?: no Interval: [27, 80] Broken balls: 1 Drop ball 2 from floor 54 Did the ball break?: no Interval: [54, 80] Broken balls: 1 Drop ball 2 from floor 63 Did the ball break?: yes Interval: [54, 62] Broken balls: 2 Drop ball 3 from floor 57 Did the ball break?: no Interval: [57, 62] Broken balls: 2 Drop ball 3 from floor 60 Did the ball break?: no Interval: [60, 62] Broken balls: 2 Drop ball 3 from floor 61 Did the ball break?: yes Interval: [60, 60] (60, 7) $
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