68 lines
1.4 KiB
Python
68 lines
1.4 KiB
Python
#!/usr/bin/env python3
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import numpy as np
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import csv
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import itertools
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import math
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import scipy.special
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#o(n) = (n-1) * o(n-2) <- pairs
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def number_pairs(size):
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if size<2:
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return 1
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n=size-1
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return n*number_pairs(size-2)
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#https://stackoverflow.com/questions/5360220/how-to-split-a-list-into-pairs-in-all-possible-ways
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def all_pairs(lst):
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if len(lst) < 2:
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yield lst
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return
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a = lst[0]
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for i in range(1,len(lst)):
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pair = (a,lst[i])
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for rest in all_pairs(lst[1:i]+lst[i+1:]):
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yield [pair] + rest
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def all_triples(lst):
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if len(lst) < 3:
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yield lst
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return
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a = lst[0]
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for i in range(1,len(lst)):
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for j in range(i+1,len(lst)):
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pair = (a,lst[i],lst[j])
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for rest in all_triples(lst[1:i]+lst[i+1:j]+lst[j+1:]):
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yield [pair] + rest
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def all_quadruples(lst):
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if len(lst) < 4:
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yield lst
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return
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a = lst[0]
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for i in range(1,len(lst)):
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for j in range(i+1,len(lst)):
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for k in range(j+1,len(lst)):
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pair = (a,lst[i],lst[j],lst[k])
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for rest in all_quadruples(lst[1:i]+lst[i+1:j]+lst[j+1:k]+lst[k+1:]):
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yield [pair] + rest
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#a=[1,2,3,4]
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a=[1,2,3,4,5,6]
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print(number_pairs(24))
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count=0
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for i in all_pairs(a):
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count+=1
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#print(i)
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print(count)
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