I was solving the question from the website CodeChef.
I found this question:
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 Sample Output
ambiguous not ambiguous ambiguous
for x in value:
for x in list:
for a in result:
For this kind of things, before doubting your code it's better to double-check that the way you handle input and output match what's expected.
I know how silly you feel when you realize you fail the tests despite a correct algorithm, for something like using the string
non-ambiguous instead of the expected