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23 lines
537 B
23 lines
537 B
#! /usr/bin/env python3
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# find the intersection of two lists including duplicate values
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from collections import defaultdict
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def frequencies(xs):
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freqs = defaultdict(int)
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for x in xs:
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freqs[x] += 1
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return freqs
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def intersection(xs, ys):
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freqs1 = frequencies(xs)
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freqs2 = frequencies(ys)
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intersection = []
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for k, v in freqs1.items():
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n = min(v, freqs2[k])
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intersection.extend([k for _ in range(n)])
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return intersection
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print(intersection([1,4,2,6,10,4,4], [7,4,9,10,20,4,10]))
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