{ "data": { "question": { "questionId": "2241", "questionFrontendId": "2122", "categoryTitle": "Algorithms", "boundTopicId": 1174202, "title": "Recover the Original Array", "titleSlug": "recover-the-original-array", "content": "
Alice had a 0-indexed array arr
consisting of n
positive integers. She chose an arbitrary positive integer k
and created two new 0-indexed integer arrays lower
and higher
in the following manner:
lower[i] = arr[i] - k
, for every index i
where 0 <= i < n
higher[i] = arr[i] + k
, for every index i
where 0 <= i < n
Unfortunately, Alice lost all three arrays. However, she remembers the integers that were present in the arrays lower
and higher
, but not the array each integer belonged to. Help Alice and recover the original array.
Given an array nums
consisting of 2n
integers, where exactly n
of the integers were present in lower
and the remaining in higher
, return the original array arr
. In case the answer is not unique, return any valid array.
Note: The test cases are generated such that there exists at least one valid array arr
.
\n
Example 1:
\n\n\nInput: nums = [2,10,6,4,8,12]\nOutput: [3,7,11]\nExplanation:\nIf arr = [3,7,11] and k = 1, we get lower = [2,6,10] and higher = [4,8,12].\nCombining lower and higher gives us [2,6,10,4,8,12], which is a permutation of nums.\nAnother valid possibility is that arr = [5,7,9] and k = 3. In that case, lower = [2,4,6] and higher = [8,10,12]. \n\n\n
Example 2:
\n\n\nInput: nums = [1,1,3,3]\nOutput: [2,2]\nExplanation:\nIf arr = [2,2] and k = 1, we get lower = [1,1] and higher = [3,3].\nCombining lower and higher gives us [1,1,3,3], which is equal to nums.\nNote that arr cannot be [1,3] because in that case, the only possible way to obtain [1,1,3,3] is with k = 0.\nThis is invalid since k must be positive.\n\n\n
Example 3:
\n\n\nInput: nums = [5,435]\nOutput: [220]\nExplanation:\nThe only possible combination is arr = [220] and k = 215. Using them, we get lower = [5] and higher = [435].\n\n\n
\n
Constraints:
\n\n2 * n == nums.length
1 <= n <= 1000
1 <= nums[i] <= 109
arr
.Alice 有一个下标从 0 开始的数组 arr
,由 n
个正整数组成。她会选择一个任意的 正整数 k
并按下述方式创建两个下标从 0 开始的新整数数组 lower
和 higher
:
0 <= i < n
的下标 i
,lower[i] = arr[i] - k
0 <= i < n
的下标 i
,higher[i] = arr[i] + k
不幸地是,Alice 丢失了全部三个数组。但是,她记住了在数组 lower
和 higher
中出现的整数,但不知道每个整数属于哪个数组。请你帮助 Alice 还原原数组。
给你一个由 2n 个整数组成的整数数组 nums
,其中 恰好 n
个整数出现在 lower
,剩下的出现在 higher
,还原并返回 原数组 arr
。如果出现答案不唯一的情况,返回 任一 有效数组。
注意:生成的测试用例保证存在 至少一个 有效数组 arr
。
\n\n
示例 1:
\n\n输入:nums = [2,10,6,4,8,12]\n输出:[3,7,11]\n解释:\n如果 arr = [3,7,11] 且 k = 1 ,那么 lower = [2,6,10] 且 higher = [4,8,12] 。\n组合 lower 和 higher 得到 [2,6,10,4,8,12] ,这是 nums 的一个排列。\n另一个有效的数组是 arr = [5,7,9] 且 k = 3 。在这种情况下,lower = [2,4,6] 且 higher = [8,10,12] 。\n\n\n
示例 2:
\n\n输入:nums = [1,1,3,3]\n输出:[2,2]\n解释:\n如果 arr = [2,2] 且 k = 1 ,那么 lower = [1,1] 且 higher = [3,3] 。\n组合 lower 和 higher 得到 [1,1,3,3] ,这是 nums 的一个排列。\n注意,数组不能是 [1,3] ,因为在这种情况下,获得 [1,1,3,3] 唯一可行的方案是 k = 0 。\n这种方案是无效的,k 必须是一个正整数。\n\n\n
示例 3:
\n\n输入:nums = [5,435]\n输出:[220]\n解释:\n唯一可行的组合是 arr = [220] 且 k = 215 。在这种情况下,lower = [5] 且 higher = [435] 。\n\n
\n\n
提示:
\n\n2 * n == nums.length
1 <= n <= 1000
1 <= nums[i] <= 109
arr
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