Hey CodeWarrior,

we've got a lot to code today!

I hope you know the basic string manipulation methods, because this kata will be all about them.

Here we go...

## Background

We've got a very long string, containing a bunch of User IDs. This string is a listing, which seperates each user ID with a comma and a whitespace ("' "). Sometimes there are more than only one whitespace. Keep this in mind! Futhermore, some user Ids are written only in lowercase, others are mixed lowercase and uppercase characters. Each user ID starts with the same 3 letter "uid", e.g. "uid345edj". But that's not all! Some stupid student edited the string and added some hashtags (#). User IDs containing hashtags are invalid, so these hashtags should be removed!

## Task

1.  Remove all hashtags
2.  Remove the leading "uid" from each user ID
3.  Return an array of strings --> split the string
4.  Each user ID should be written in only lowercase characters
5.  Remove leading and trailing whitespaces

---

## Note

Even if this kata can be solved by using Regex or Linq, please try to find a solution by using only C#'s string class.

Some references for C#:

- [Microsoft MDSN: Trim](https://msdn.microsoft.com/de-de/library/t97s7bs3%28v=vs.110%29.aspx)
- [Microsoft MSDN: Split](https://msdn.microsoft.com/de-de/library/tabh47cf%28v=vs.110%29.aspx)
- [Microsoft MSDN: ToLower](https://msdn.microsoft.com/en-us/library/system.string.tolower%28v=vs.110%29.aspx)
- [Microsoft MSDN: Replace](https://msdn.microsoft.com/de-de/library/fk49wtc1%28v=vs.110%29.aspx)
- [Microsoft MSDN: Substring](https://msdn.microsoft.com/de-de/library/aka44szs%28v=vs.110%29.aspx)

```python

USER_FILENAME = "<user_code>"
import sys, json, builtins
import math, heapq, bisect, itertools, functools, collections, statistics, fractions, decimal, operator, array, random, re, string, os, pathlib
try:
    import resource as _res
except Exception:
    _res = None
from collections import Counter, defaultdict, deque, OrderedDict
from functools import lru_cache, reduce
from itertools import accumulate, permutations, combinations, product
from math import gcd, ceil, floor, sqrt
from decimal import Decimal
try:
    from typing import *
except Exception:
    pass
try:
    sys.setrecursionlimit(1_000_000)
except Exception:
    pass
try:
    import site as _site
    try:
        _sys_sites = _site.getsitepackages() if hasattr(_site, "getsitepackages") else []
        for _p in _sys_sites:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
    try:
        _usp = _site.getusersitepackages()
        if isinstance(_usp, str):
            _usp = [_usp]
        for _p in _usp:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
except Exception:
    pass

def _disabled_input(*args, **kwargs):
    raise RuntimeError("input() is disabled in callable mode")
builtins.input = _disabled_input

ns = {"__name__": "__judge__"}  # prevent if __name__ == "__main__" blocks
for _k, _v in list(globals().items()):
    if not _k.startswith("_"):
        ns[_k] = _v
_CODE = "def get_users_ids(s):\n    s=s.replace('#', '').lower()\n    r = [e.rstrip().strip() for e in s.split(', ')]\n    r = [e[3:].strip() if e[:3]=='uid' else e for e in r]\n    return r"
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'get_users_ids'
if _fn_name:
    if "Solution" in ns:
        try:
            _obj = ns["Solution"]()
            if hasattr(_obj, _fn_name):
                _target = getattr(_obj, _fn_name)
        except Exception:
            _target = None
    if _target is None and _fn_name in ns and callable(ns[_fn_name]):
        _target = ns[_fn_name]
# Fallback: if there's exactly one user-defined function, use it
if _target is None:
    _cands = [v for k, v in ns.items() if callable(v) and getattr(v, "__module__", "") in ("__judge__", "__main__")]
    _user_funcs = [c for c in _cands if getattr(c, "__name__", "").startswith("_") is False]
    if len(_user_funcs) == 1:
        _target = _user_funcs[0]
if _target is None:
    raise RuntimeError(f"Could not resolve callable '{_fn_name}'")

_raw = sys.stdin.read().strip()
if _raw:
    _parsed = json.loads(_raw)
    if isinstance(_parsed, dict):
        _kwargs = _parsed.get("kwargs", {})
        _args = _parsed.get("args", [])
    else:
        _args, _kwargs = _parsed, {}
else:
    _args, _kwargs = [], {}
if not isinstance(_args, (list, tuple)):
    _args = [_args]
_res = _target(*_args, **_kwargs)
try:
    sys.stdout.write(repr(_res) + "\n")
except Exception:
    pass

```

Measured memory_bytes: 5766