'''
https://app.codility.com/demo/results/demoHZEZJ5-D8X/



This is a demo task.
Write a function:

    def solution(A)

that, given an array A of N integers, returns the smallest positive integer (greater than 0) that does not occur in A.

For example, given A = [1, 3, 6, 4, 1, 2], the function should return 5.

Given A = [1, 2, 3], the function should return 4.

Given A = [−1, −3], the function should return 1.

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 [−1,000,000..1,000,000].

'''


# you can write to stdout for debugging purposes, e.g.
# print("this is a debug message")

def solution(A):
    # write your code in Python 3.6
    pos_set = set()
    for a in A:
        if a > 0:
            pos_set.add(a)
    pos = list(pos_set)
    pos.sort()

    res = 1
    for num in pos:
        if res < num:
            break
        else:
            res = num + 1
    return res
Implement MissingInteger (microsoft oa demo)
Implement MissingInteger (microsoft oa demo)
