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.
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.
For each test case output whether the permutation is ambiguous or not. Adhere to the format shown in the sample output.
4 1 4 3 2 5 2 3 4 5 1 1 1 0
ambiguous not ambiguous ambiguous
Passages like these must be given in CAT to f*c* peoples' brain.
Last edit: 2016-06-21 21:38:27
easy question :)
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.?
WA for "ambigous" instead of "ambiguous" :(
Spent so much time getting the WA. The problem was in word spelling: it is "ambiguous", not "ambigious". Oh, English...
AC in 2nd go ...did a silly mistake..:)