28 lines
1.7 KiB
Plaintext
28 lines
1.7 KiB
Plaintext
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--- Part Two ---
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Your analysis only confirmed what everyone feared: the two lists of location IDs are indeed very different.
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Or are they?
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The Historians can't agree on which group made the mistakes or how to read most of the Chief's handwriting, but in the commotion you notice an interesting detail: a lot of location IDs appear in both lists! Maybe the other numbers aren't location IDs at all but rather misinterpreted handwriting.
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This time, you'll need to figure out exactly how often each number from the left list appears in the right list. Calculate a total similarity score by adding up each number in the left list after multiplying it by the number of times that number appears in the right list.
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Here are the same example lists again:
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3 4
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4 3
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2 5
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1 3
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3 9
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3 3
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For these example lists, here is the process of finding the similarity score:
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The first number in the left list is 3. It appears in the right list three times, so the similarity score increases by 3 * 3 = 9.
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The second number in the left list is 4. It appears in the right list once, so the similarity score increases by 4 * 1 = 4.
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The third number in the left list is 2. It does not appear in the right list, so the similarity score does not increase (2 * 0 = 0).
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The fourth number, 1, also does not appear in the right list.
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The fifth number, 3, appears in the right list three times; the similarity score increases by 9.
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The last number, 3, appears in the right list three times; the similarity score again increases by 9.
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So, for these example lists, the similarity score at the end of this process is 31 (9 + 4 + 0 + 0 + 9 + 9).
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Once again consider your left and right lists. What is their similarity score?
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