Winston Liek

Ranch Hand

Posts: 194

posted 3 years ago

First of all, here is the problem description:

Here is my solution to the problem:

But evertime I run it, I am gettign an error:

Here is my sample test data:

[4, 1, 3, 2]

I'm certain that it should not give any runtime errors. But why? Is this a bug?

A non-empty zero-indexed array A consisting of N integers is given.

A permutation is a sequence containing each element from 1 to N once, and only once.

For example, array A such that:

A[0] = 4

A[1] = 1

A[2] = 3

A[3] = 2

is a permutation, but array A such that:

A[0] = 4

A[1] = 1

A[2] = 3

is not a permutation.

The goal is to check whether array A is a permutation.

Write a function:

class Solution { public int solution(int[] A); }

that, given a zero-indexed array A, returns 1 if array A is a permutation and 0 if it is not.

For example, given array A such that:

A[0] = 4

A[1] = 1

A[2] = 3

A[3] = 2

the function should return 1.

Given array A such that:

A[0] = 4

A[1] = 1

A[2] = 3

the function should return 0.

Assume that:

N is an integer within the range [1..100,000];

each element of array A is an integer within the range [1..1,000,000,000].

Complexity:

expected worst-case time complexity is O(N);

expected worst-case space complexity is O(N), beyond input storage (not counting the storage required for input arguments).

Here is my solution to the problem:

But evertime I run it, I am gettign an error:

Running solution...

Compilation successful

Example test : example1 - OK

example2 - RUNTIME ERROR (tested program terminated unexpectedly)

Output:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 4

at Solution.solution(Solution.java:12)

at wrapper.run(wrapper.java:27)

at wrapper.main(wrapper.java:20)

Detected some errors.

Here is my sample test data:

[4, 1, 3, 2]

I'm certain that it should not give any runtime errors. But why? Is this a bug?

Amar Saikia

Ranch Hand

Posts: 43

2

posted 3 years ago

I have tested the code using java 7 compiler and its working fine without giving any run time exception with the sample you have provided.

Having said that, I must say the logic you have applied will give you run time exception for different type inputs. Consider a sample array [14, 1, 2,3 ] . The size will be 4. Now the code will create an array B with size 5.

So far so good. But now, will give you ArrayIndexOutOfBoundsException as B[14] is non existent. So, you will have to change the logic to get it work properly.

Having said that, I must say the logic you have applied will give you run time exception for different type inputs. Consider a sample array [14, 1, 2,3 ] . The size will be 4. Now the code will create an array B with size 5.

So far so good. But now, will give you ArrayIndexOutOfBoundsException as B[14] is non existent. So, you will have to change the logic to get it work properly.

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