{ "data": { "question": { "questionId": "2117", "questionFrontendId": "2007", "boundTopicId": null, "title": "Find Original Array From Doubled Array", "titleSlug": "find-original-array-from-doubled-array", "content": "

An integer array original is transformed into a doubled array changed by appending twice the value of every element in original, and then randomly shuffling the resulting array.

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Given an array changed, return original if changed is a doubled array. If changed is not a doubled array, return an empty array. The elements in original may be returned in any order.

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Example 1:

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\nInput: changed = [1,3,4,2,6,8]\nOutput: [1,3,4]\nExplanation: One possible original array could be [1,3,4]:\n- Twice the value of 1 is 1 * 2 = 2.\n- Twice the value of 3 is 3 * 2 = 6.\n- Twice the value of 4 is 4 * 2 = 8.\nOther original arrays could be [4,3,1] or [3,1,4].\n
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Example 2:

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\nInput: changed = [6,3,0,1]\nOutput: []\nExplanation: changed is not a doubled array.\n
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Example 3:

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\nInput: changed = [1]\nOutput: []\nExplanation: changed is not a doubled array.\n
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Constraints:

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