Spoj Problem-PERMUT2 - Ambiguous Permutations

PERMUT2 - Ambiguous Permutations [Java Program]

Link:-

http://www.spoj.com/problems/PERMUT2/

Problem Statement:-

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 1and 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.

Input 

4

1 4 3 2

5

2 3 4 5 1

1

1

0

Output 

ambiguous

not ambiguous

ambiguous

Java Program:-

/**

 * @(#)PERMUT2.java

 *

 *

 * @author Suyash Bhalla

 * @version 1.00 2015/4/23

 */

import java.io.*;

class PERMUT2 {

    public static void main(String args[])throws IOException{

   

    BufferedReader br=new BufferedReader(new InputStreamReader(System.in));

    int n=Integer.parseInt(br.readLine());

    while(n!=0){

    int per[]=new int[n+1];

    int inper[]=new int[n+1];

    String str[]=br.readLine().split(" ");

    for(int i=1;i<=n;i++){

    per[i]=Integer.parseInt(str[i-1]);

    inper[per[i]]=i;

    }

    boolean isAmbigous=true;

    for(int i=1;i<=n;i++){

    if(per[i]!=inper[i]){

    isAmbigous=false;

    break;

    }

    }

    if(isAmbigous){

    System.out.println("ambiguous");

    }else{

    System.out.println("not ambiguous");

    }

    n=Integer.parseInt(br.readLine());

    }

   

    }

    

    

}

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