PERMUT2 - Ambiguous Permutations


Some programming contest problems are really tricky: not only do they require a different output format from what you might have expected, but also the sample output does not show the difference. For an example, let us look at permutations.
A permutation of the integers 1 to n is an ordering of these integers. So the natural way to represent a permutation is to list the integers in this order. With n = 5, a permutation might look like 2, 3, 4, 5, 1.
However, there is another possibility of representing a permutation: You create a list of numbers where the i-th number is the position of the integer i in the permutation. Let us call this second possibility an inverse permutation. The inverse permutation for the sequence above is 5, 1, 2, 3, 4.
An ambiguous permutation is a permutation which cannot be distinguished from its inverse permutation. The permutation 1, 4, 3, 2 for example is ambiguous, because its inverse permutation is the same. To get rid of such annoying sample test cases, you have to write a program which detects if a given permutation is ambiguous or not.

Input Specification

The input contains several test cases.
The first line of each test case contains an integer n (1 ≤ n ≤ 100000). Then a permutation of the integers 1 to n follows in the next line. There is exactly one space character between consecutive integers. You can assume that every integer between 1 and n appears exactly once in the permutation.
The last test case is followed by a zero.

Output Specification

For each test case output whether the permutation is ambiguous or not. Adhere to the format shown in the sample output.

Sample Input

4
1 4 3 2
5
2 3 4 5 1
1
1
0

Sample Output

ambiguous
not ambiguous
ambiguous

hide comments
masterx001: 2016-09-25 11:31:52

http://adf.ly/1eEfak

nikhil03: 2016-08-23 23:14:58

Easy question, AC in a go!!!
Try NOT to read it again and again if not getting the question.
Rather, read it after sometime.

Saif : 2016-08-22 19:55:35

@ragnerok Read the problem statement again ,you are already given a permutation

ragnerok: 2016-08-18 20:31:40

I dont get it whats the natural way to represent a permutation ?
Please help

xinnix: 2016-07-11 08:34:59

Passages like these must be given in CAT to f*c* peoples' brain.

adi_1996: 2016-06-24 05:55:46

cakewalk :D

Akash Saha: 2016-06-21 17:38:25

Last edit: 2016-06-21 21:38:27
gautam: 2016-04-03 12:36:27

easy one....;-)

utkarsh538: 2016-03-31 07:09:42

easy question :)

chalarangelo: 2016-03-15 20:09:11

I have submitted multiple solutions in Python 3.4 and all give wrong answer, although I checked with a whole lot of input and the output is corret. Is there some formatting trick I need to know like end of lines etc.?


Added by:Adrian Kuegel
Date:2005-06-24
Time limit:10s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: NODEJS PERL 6 VB.net
Resource:own problem, used in University of Ulm Local Contest 2005