youngmaids

youngmaids

Problem Statement

Let N be a positive even number.

We have a permutation of (1, 2, ..., N), p = (p1, p2, ..., pN). Snuke is constructing another permutation of (1, 2, ..., N), q, following the procedure below.

First, let q be an empty sequence. Then, perform the following operation until p becomes empty:

  • Select two adjacent elements in p, and call them x and y in order. Remove x and y from p (reducing the length of p by 2), and insert x and y, preserving the original order, at the beginning of q.

When p becomes empty, q will be a permutation of (1, 2, ..., N).

Find the lexicographically smallest permutation that can be obtained as q.

Constraints

  • N is an even number.
  • 2 ≤ N ≤ 2 × 105
  • p is a permutation of (1, 2, ..., N).

Input

Input is given from Standard Input in the following format:

N
p1 p2 ... pN

Output

Print the lexicographically smallest permutation, with spaces in between.

Sample Input 1

4
3 2 4 1

Sample Output 1

3 1 2 4

The solution above is obtained as follows:

p q
(3, 2, 4, 1) ()
(3, 1) (2, 4)
() (3, 1, 2, 4)

Sample Input 2

2
1 2

Sample Output 2

1 2

Sample Input 3

8
4 6 3 2 8 5 7 1

Sample Output 3

3 1 2 7 4 6 8 5

The solution above is obtained as follows:

p q
(4, 6, 3, 2, 8, 5, 7, 1) ()
(4, 6, 3, 2, 7, 1) (8, 5)
(3, 2, 7, 1) (4, 6, 8, 5)
(3, 1) (2, 7, 4, 6, 8, 5)
() (3, 1, 2, 7, 4, 6, 8, 5)

Submitting .cpp to 'youngmaids'


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Compile Errors


							
Time Limit: 2 Seconds
Memory Limit: 1024MB
No. of ACs: 3
Your best score: 0
Source: Dunjudge Archive

Subtask Score
1 100
2 0