2097. Valid Arrangement of Pairs
Description
You are given a 0-indexed 2D integer array pairs
where pairs[i] = [starti, endi]
. An arrangement of pairs
is valid if for every index i
where 1 <= i < pairs.length
, we have endi-1 == starti
.
Return any valid arrangement of pairs
.
Note: The inputs will be generated such that there exists a valid arrangement of pairs
.
Example 1:
Input: pairs = [[5,1],[4,5],[11,9],[9,4]] Output: [[11,9],[9,4],[4,5],[5,1]] Explanation: This is a valid arrangement since endi-1 always equals starti. end0 = 9 == 9 = start1 end1 = 4 == 4 = start2 end2 = 5 == 5 = start3
Example 2:
Input: pairs = [[1,3],[3,2],[2,1]] Output: [[1,3],[3,2],[2,1]] Explanation: This is a valid arrangement since endi-1 always equals starti. end0 = 3 == 3 = start1 end1 = 2 == 2 = start2 The arrangements [[2,1],[1,3],[3,2]] and [[3,2],[2,1],[1,3]] are also valid.
Example 3:
Input: pairs = [[1,2],[1,3],[2,1]] Output: [[1,2],[2,1],[1,3]] Explanation: This is a valid arrangement since endi-1 always equals starti. end0 = 2 == 2 = start1 end1 = 1 == 1 = start2
Constraints:
1 <= pairs.length <= 105
pairs[i].length == 2
0 <= starti, endi <= 109
starti != endi
- No two pairs are exactly the same.
- There exists a valid arrangement of
pairs
.
Solutions
Solution 1
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