#Unflatten a list (Easy)

There are several katas like "Flatten a list".
These katas are done by so many warriors, that the count of available list to flattin goes down!

So you have to build a method, that creates new arrays, that can be flattened!

#Shorter: You have to unflatten a list/an array.

You get an array of integers and have to unflatten it by these rules:
```
- You start at the first number.
- If this number x is smaller than 3, take this number x direct 
  for the new array and continue with the next number.
- If this number x is greater than 2, take the next x numbers (inclusive this number) as a 
  sub-array in the new array. Continue with the next number AFTER this taken numbers.
- If there are too few numbers to take by number, take the last available numbers.
```

The given array will always contain numbers. There will only be numbers > 0.

Example:
```
 [1,4,5,2,1,2,4,5,2,6,2,3,3] -> [1,[4,5,2,1],2,[4,5,2,6],2,[3,3]]

Steps: 
1. The 1 is added directly to the new array.
2. The next number is 4. So the next 4 numbers (4,5,2,1) are added as sub-array in the new array.
3. The 2 is added directly to the new array.
4. The next number is 4. So the next 4 numbers (4,5,2,6) are added as sub-array in the new array.
5. The 2 is added directly to the new array.
6. The next number is 3. So the next 3 numbers would be taken. There are only 2, 
   so take these (3,3) as sub-array in the new array.
```

There is a harder version of this kata!
Unflatten a list (Harder than easy)

Have fun coding it and please don't forget to vote and rank this kata! :-) 

I have created other katas. Have a look if you like coding and challenges.

```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 unflatten(arr):\n  \n  j = 0\n  res = []\n  \n  for x in arr:\n    if j > 0:\n      res[-1].append(x)\n      j -= 1\n    elif x < 3:\n      res.append(x)\n    else:\n      res.append([x])\n      j = x-1\n  \n  return res'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'unflatten'
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: 5680