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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
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 PERL6 VB.NET |
Resource: | own problem, used in University of Ulm Local Contest 2005 |
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2015-08-30 07:43:39 kartikay singh
last test case by 0 ;) missed that :( |
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2015-08-27 04:21:31 Mohit
got AC in first attempt.? be care only about " the i-th number is the position of the integer i in the permutation" |
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2015-08-22 01:34:02 Shivam Singh
Green at first sight after a long time :P :D |
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2015-08-18 21:07:05 suhas
My 20th :). got WA coz used "non" instead of "not" :/ |
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2015-08-14 19:21:51 Babu
very very easy |
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2015-07-24 06:03:23
nice question!! |
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2015-07-22 19:58:11 Vivek
Easy.AC in 1st go. Read this statement multiple time " You create a list of numbers where the i-th number is the position of the integer i in the permutation" . the " i'th number" represents the number at i'th position in the give permutation. |
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2015-07-16 18:48:50 Akshay Aradhya
Little Confusing but Easy :P And LOL 10 second Time limit hahahah |
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2015-07-11 14:27:24 poojan
ac in 1 go too easy |
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2015-06-24 01:15:37 ritu
AC in frst :D |