Find gaps in a sequence of Strings

Question

I have got a sequence of strings - 0000001, 0000002, 0000003.... upto 2 million. They are not contiguous. Meaning there are gaps. Say after 0000003 the next str

Answer 1

For storing sequence of 2 millions ints you can use bitarray. Here each bit means one integer (the integer of that index in bitarray). Example code:

gaps = []
# bitarray is 0 based
a = bitarray.bitarray(total + 1)
a.setall(False)
for sid in curr_ids:
    a[int(sid)] = True
for i in range(1, total):
    if not a[i]:
        gaps.append('%07d' %(i))
return gaps