{ "data": { "question": { "questionId": "842", "questionFrontendId": "822", "boundTopicId": null, "title": "Card Flipping Game", "titleSlug": "card-flipping-game", "content": "

You are given two 0-indexed integer arrays fronts and backs of length n, where the ith card has the positive integer fronts[i] printed on the front and backs[i] printed on the back. Initially, each card is placed on a table such that the front number is facing up and the other is facing down. You may flip over any number of cards (possibly zero).

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After flipping the cards, an integer is considered good if it is facing down on some card and not facing up on any card.

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Return the minimum possible good integer after flipping the cards. If there are no good integers, return 0.

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Example 1:

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\nInput: fronts = [1,2,4,4,7], backs = [1,3,4,1,3]\nOutput: 2\nExplanation:\nIf we flip the second card, the face up numbers are [1,3,4,4,7] and the face down are [1,2,4,1,3].\n2 is the minimum good integer as it appears facing down but not facing up.\nIt can be shown that 2 is the minimum possible good integer obtainable after flipping some cards.\n
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Example 2:

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\nInput: fronts = [1], backs = [1]\nOutput: 0\nExplanation:\nThere are no good integers no matter how we flip the cards, so we return 0.\n
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Constraints:

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