nome.py

def find_lowest_not_exists(array):
    max_len = len(array)-1
    min = 0
    ri = max_len
    while(ri > 0):

        idx = 0

        while(idx < ri):
            if(array[idx] <= min):
                array[ri], array[idx] = array[idx], array[ri]
                ri -= 1

            else:
                idx+=1
        if(array[ri] <= min):
            ri-=1
        idx2 = 0
        new_min = array[idx2]

        while(idx2 <= ri):
            if(array[idx2] < new_min ):
                new_min = array[idx2]
            idx2+=1

        print(array,min,new_min)
        if(new_min - min > 1):
            return max(min+1,new_min-1)

        min = new_min

    return new_min+1