A Math Contest P3 - LIS Reconstruction
View as PDFConsider a permutation of the first  positive integers, 
. Define 
 as the length of the longest increasing subsequence of 
.
Given , find the lexicographically minimal possible permutation 
, or determine that no such permutation exists.
Constraints
Input Specification
The first line contains an integer, .
The second line contains  space-separated integers, 
.
Output Specification
If there is no sequence  that can produce sequence 
, output 
; otherwise, output one line containing 
 positive integers, representing the lexicographically minimal permutation 
.
Sample Input 1
3
1 2 2
Sample Output 1
1 3 2
Explanation for Sample Output 1
Note that
- The longest increasing subsequence of 
is
.
 - The longest increasing subsequence of 
is
.
 - One of the longest increasing subsequences of 
is
.
 
Sample Input 2
3
1 2 1
Sample Output 2
-1
Explanation for Sample Output 2
No possible permutation  exists.
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