Welcome

This kata is inspired by This Kata


We have a string s

We have a number n

Here is a function that takes your string, concatenates the even-indexed chars to the front, odd-indexed chars to the back.

Examples

    s = "Wow Example!"
    result = "WwEapeo xml!"
    s = "I'm JomoPipi"
    result = "ImJm ii' ooPp"
    
The Task:

return the result of the string after applying the function to it n times.

example where s = "qwertyuio" and n = 2:

    after 1 iteration  s = "qetuowryi"
    after 2 iterations s = "qtorieuwy"
    return "qtorieuwy"

 Note 

there's a lot of tests, big strings,
and n is greater than a billion

so be ready to optimize.

after doing this: do it's best friend!

# Check out my other kata!

        
Matrix Diagonal Sort OMG
String -> N iterations -> String
String -> X iterations -> String
ANTISTRING
Array - squareUp b!
Matrix - squareUp b!
Infinitely Nested Radical Expressions
pipi Numbers!

```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 = '#Kata: String -> N iterations -> String  Rating 5kyu\n\n\n#To optimize this problem, we must look at the circular (modular) nature of the iterations\n#of the even/odd rule.  Given any string, under the even/odd rule, the number of permutations\n#will be no longer than the length of the original message.  \n# e.g. \'abcdefghijklmnop\' has only four unique permutations under the even/odd rule:\n#      [\'abcdefghijklmnop\', \'acegikmobdfhjlnp\', \'aeimbfjncgkodhlp\', \'aibjckdlemfngohp\']\n# So, if we want to apply the even/odd rule N times for string \'abcdefghijklmnop\', we need but\n# access the \'N modulo n\' element in the permutation list (where m is the length of permutation list)\n\n\ndef buildPermList(originalMsg):\n    \n    listPerms = []\n    listPerms.append(originalMsg)   #index 0 is original message\n    curMsg = originalMsg\n    \n    while True:\n        even = curMsg[0::2]\n        odd = curMsg[1::2]\n        curMsg = even+odd\n        if curMsg != originalMsg:   #Scenario: Back to the original message\n            listPerms.append(curMsg)\n        else:\n            break\n\n    #listPerms is <= the length of the origianl message; ith element is the ith permutation under\n    # the even/odd rules\n    return listPerms    \n#-----end function\n\n\ndef jumbled_string(msg, n):\n\n    permList = buildPermList(msg)\n    numUniquePerms = len(permList)\n    desiredRotIndex = n % numUniquePerms\n\n    return permList[desiredRotIndex]\n\n#-----end function\n\n\n#Demonstrative test code\n# msg = \'abcdefghijklmnop\'\n# n=18\n# myList = buildPermList(msg)\n# print("---Length of list: ", len(myList))\n# print("---List: ", myList)\n# lenList = len(myList)\n# desiredIndex = n % lenList\n# print( "The location: ", str(desiredIndex) )\n# print( "Desired String",  rotationsByN(msg, n) )\n'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'jumbled_string'
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: 5685