Class Solution
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- All Implemented Interfaces:
public final class Solution2097 - Valid Arrangement of Pairs.
Hard
You are given a 0-indexed 2D integer array
pairswhere <code>pairsi = start<sub>i</sub>, end<sub>i</sub></code>. An arrangement ofpairsis valid if for every indexiwhere1 <= i < pairs.length, we have <code>end<sub>i-1</sub> == start<sub>i</sub></code>.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 end<sub>i-1</sub> always equals start<sub>i</sub>.
end<sub>0</sub> = 9 == 9 = start<sub>1</sub>
end<sub>1</sub> = 4 == 4 = start<sub>2</sub>
end<sub>2</sub> = 5 == 5 = start<sub>3</sub>
Example 2:
Input: pairs = \[\[1,3],3,2,2,1]
Output: [1,3,3,2,2,1]
Explanation:
This is a valid arrangement since end<sub>i-1</sub> always equals start<sub>i</sub>.
end<sub>0</sub> = 3 == 3 = start<sub>1</sub>
end<sub>1</sub> = 2 == 2 = start<sub>2</sub>
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 end<sub>i-1</sub> always equals start<sub>i</sub>.
end<sub>0</sub> = 2 == 2 = start<sub>1</sub>
end<sub>1</sub> = 1 == 1 = start<sub>2</sub>
Constraints:
<code>1 <= pairs.length <= 10<sup>5</sup></code>
pairs[i].length == 2<code>0 <= start<sub>i</sub>, end<sub>i</sub><= 10<sup>9</sup></code>
<code>start<sub>i</sub> != end<sub>i</sub></code>
No two pairs are exactly the same.
There exists a valid arrangement of
pairs.