A non-empty 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, because value 2 is missing.

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

Write a function:

def solution(A)

that, given an 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.

Write an efficient algorithm for the following assumptions:

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].

```
def solution(A):
# write your code in Python 3.6
A = sorted(A)
length = len(A)
if length != A[length-1]:
return 0
for i, v in enumerate(A):
if i + 1 != v:
return 0
return 1
```

Detected time complexity: `O(N) or O(N * log(N))`