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| """
思路
in_put = 'abc'
n = 3個字元
組合數量 = n^n = 3^3 = 27
Big O: O(n^n)
"""
def virtual_code():
answer = []
for v1 in 'abc':
for v2 in 'abc':
for v3 in 'abc':
print(v1+v2+v3)
answer.append(v1+v2+v3)
"""
foreach(n)+foreach(n)+foreach(n)
a - a - a =>aaa
- b =>aab
- c =>aac
a - b - a =>aba
- b =>abb
- c =>abc
a - c - a =>aca
- b =>acb
- c =>acc
b - a - a =>baa
- b =>bab
- c =>bac
b - b - a =>bba
- b =>bbb
- c =>bbc
b - c - a =>bca
- b =>bcb
- c =>bcc
c - a - a =>caa
- b =>cab
- c =>cac
c - b - a =>cba
- b =>cbb
- c =>cbc
c - c - a =>cca
- b =>ccb
- c =>ccc
"""
"""
遞迴過程:
combi(in_put='abc', next_size=3, prefix='')
combi(in_put='abc', next_size=2, prefix='a')
combi(in_put='abc', next_size=1, prefix='aa')
combi(in_put='abc', next_size=0, prefix='aaa') =>answer.append(prefix)
combi(in_put='abc', next_size=0, prefix='aab') =>answer.append(prefix)
combi(in_put='abc', next_size=0, prefix='aac') =>answer.append(prefix)
combi(in_put='abc', next_size=1, prefix='ab')
combi(in_put='abc', next_size=0, prefix='aba') =>answer.append(prefix)
combi(in_put='abc', next_size=0, prefix='abb') =>answer.append(prefix)
combi(in_put='abc', next_size=0, prefix='abc') =>answer.append(prefix)
combi(in_put='abc', next_size=1, prefix='ac')
combi(in_put='abc', next_size=0, prefix='aca') =>answer.append(prefix)
combi(in_put='abc', next_size=0, prefix='acb') =>answer.append(prefix)
combi(in_put='abc', next_size=0, prefix='acc') =>answer.append(prefix)
combi(in_put='abc', next_size=2, prefix='b')
combi(in_put='abc', next_size=1, prefix='ba')
combi(in_put='abc', next_size=0, prefix='baa') =>answer.append(prefix)
combi(in_put='abc', next_size=0, prefix='bab') =>answer.append(prefix)
combi(in_put='abc', next_size=0, prefix='bac') =>answer.append(prefix)
combi(in_put='abc', next_size=1, prefix='bb')
combi(in_put='abc', next_size=0, prefix='bba') =>answer.append(prefix)
combi(in_put='abc', next_size=0, prefix='bbb') =>answer.append(prefix)
combi(in_put='abc', next_size=0, prefix='bbc') =>answer.append(prefix)
combi(in_put='abc', next_size=1, prefix='bc')
combi(in_put='abc', next_size=0, prefix='bca') =>answer.append(prefix)
combi(in_put='abc', next_size=0, prefix='bcb') =>answer.append(prefix)
combi(in_put='abc', next_size=0, prefix='bcc') =>answer.append(prefix)
combi(in_put='abc', next_size=2, prefix='c')
combi(in_put='abc', next_size=1, prefix='ca')
combi(in_put='abc', next_size=0, prefix='caa') =>answer.append(prefix)
combi(in_put='abc', next_size=0, prefix='cab') =>answer.append(prefix)
combi(in_put='abc', next_size=0, prefix='cac') =>answer.append(prefix)
combi(in_put='abc', next_size=1, prefix='cb')
combi(in_put='abc', next_size=0, prefix='cba') =>answer.append(prefix)
combi(in_put='abc', next_size=0, prefix='cbb') =>answer.append(prefix)
combi(in_put='abc', next_size=0, prefix='cbc') =>answer.append(prefix)
combi(in_put='abc', next_size=1, prefix='cc')
combi(in_put='abc', next_size=0, prefix='cca') =>answer.append(prefix)
combi(in_put='abc', next_size=0, prefix='ccb') =>answer.append(prefix)
combi(in_put='abc', next_size=0, prefix='ccc') =>answer.append(prefix)
"""
def combi(in_put, next_size, prefix=""):
if next_size == 0:
answer.append(prefix)
return
for i in range(0, len(in_put)):
combi(in_put=in_put,
next_size=next_size - 1,
prefix=f'{prefix}{in_put[i]}',
)
answer = []
in_put = "abc"
combi(in_put, len(in_put))
print("\n".join(answer))
|
