shiva kumar shiva kumar - 2 months ago 9
Python Question

is there a loop in my logic-python

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.

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


I post the following python code but they said my answer is wrong
can someone help me where is the mistake in my logic?

my code goes here:

def main():
T=int(input())
result=[]
while(T!=0):
list=[]
list1=[]
y=0
value=raw_input().split(' ')
for x in value:
list.append(int(x))
for x in list:
y+=1
x=list.index(y)+1
list1.append(x)
if(list==list1):
result.append("ambiguous")
else:
result.append("non-ambiguous")
T=int(input())
for a in result:
print a
main()

Answer

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 not ambiguous.

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