- Difficulty: Medium
- Tags: LeetCode, Medium, Graph, Topological Sort, Array, leetcode-444, Breadth-First Search, O(n * s), O(n), 🔒
Problem
You are given an integer array nums
of length n
where nums
is a permutation of the integers in the range [1, n]
. You are also given a 2D integer array sequences
where sequences[i]
is a subsequence of nums
.
Check if nums
is the shortest possible and the only supersequence. The shortest supersequence is a sequence with the shortest length and has all sequences[i]
as subsequences. There could be multiple valid supersequences for the given array sequences
.
- For example, for
sequences = [[1,2],[1,3]]
, there are two shortest supersequences,[1,2,3]
and[1,3,2]
. - While for
sequences = [[1,2],[1,3],[1,2,3]]
, the only shortest supersequence possible is[1,2,3]
.[1,2,3,4]
is a possible supersequence but not the shortest.
Return true
if nums
is the only shortest supersequence for sequences
, or false
otherwise.
A subsequence is a sequence that can be derived from another sequence by deleting some or no elements without changing the order of the remaining elements.
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Example 1:
Input: nums = [1,2,3], sequences = [[1,2],[1,3]] Output: false Explanation: There are two possible supersequences: [1,2,3] and [1,3,2]. The sequence [1,2] is a subsequence of both: [1,2,3] and [1,3,2]. The sequence [1,3] is a subsequence of both: [1,2,3] and [1,3,2]. Since nums is not the only shortest supersequence, we return false.
Example 2:
Input: nums = [1,2,3], sequences = [[1,2]] Output: false Explanation: The shortest possible supersequence is [1,2]. The sequence [1,2] is a subsequence of it: [1,2]. Since nums is not the shortest supersequence, we return false.
Example 3:
Input: nums = [1,2,3], sequences = [[1,2],[1,3],[2,3]] Output: true Explanation: The shortest possible supersequence is [1,2,3]. The sequence [1,2] is a subsequence of it: [1,2,3]. The sequence [1,3] is a subsequence of it: [1,2,3]. The sequence [2,3] is a subsequence of it: [1,2,3]. Since nums is the only shortest supersequence, we return true.
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Constraints:
n == nums.length
1 <= n <= 104
nums
is a permutation of all the integers in the range[1, n]
.1 <= sequences.length <= 104
1 <= sequences[i].length <= 104
1 <= sum(sequences[i].length) <= 105
1 <= sequences[i][j] <= n
- All the arrays of
sequences
are unique. sequences[i]
is a subsequence ofnums
.