Validate if a given string is numeric.

Some examples:
"0" => true
" 0.1 " => true
"abc" => false
"1 a" => false
"2e10" => true

Note: It is intended for the problem statement to be ambiguous. You should gather all requirements up front before implementing one.

Update (2015-02-10):
The signature of the C++ function had been updated. If you still see your function signature accepts a const char * argument, please click the reload button to reset your code definition.

```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 = 'class Solution:\n     def isNumber(self, s):\n         """\n         :type s: str\n         :rtype: bool\n         """\n         \n         reg_sol = self.isNumber_regex(s)\n         aut_sol = self.isNumber_automata(s)\n         pyt_sol = self.isNumber_python(s)\n         \n         if not (reg_sol == aut_sol == pyt_sol):\n             raise Exception("\'{s}\' is {reg_sol} according to regex, {aut_sol} according to automata, {pyt_sol} according to float()".format(s=s, reg_sol=reg_sol, aut_sol=aut_sol, pyt_sol=pyt_sol))\n         \n         return aut_sol\n     \n     def isNumber_regex(self, s):\n \n         import re\n \n         pattern = re.compile(\'^ *[-+]?([0-9]*\\.[0-9]+|[0-9]+|[0-9]+\\.)([eE][-+]?([0-9]+))? *$\')\n         return None != pattern.match(s)\n     \n     transition = (\n         # 0\n         {\' \': 0,\n          \'.\': 3,\n          \'-\': 1,\n          \'0\': 2},\n         # 1\n         {\'.\': 3,\n          \'0\': 2},\n         # 2\n         {\'0\': 2,\n          \'.\': 4,\n          \'e\': 5,\n          \' \': 8},\n         # 3\n         {\'0\': 4},\n         # 4\n         {\'0\': 4,\n          \'e\': 5,\n          \' \': 8},\n         # 5\n         {\'-\': 6,\n          \'0\': 7},\n         # 6\n         {\'0\': 7},\n         # 7\n         {\'0\': 7,\n          \' \': 8},\n         # 8\n         {\' \': 8}\n         )\n     final_states = (2,4,7,8)\n     \n     def isNumber_automata(self, s):\n         \n         def key(char):\n             if char in \'\\t\':\n                 return \' \'\n             if char in \'123456789\':\n                 return \'0\'\n             if char in \'E\':\n                 return \'e\'\n             if char in \'+\':\n                 return \'-\'\n             return char\n         \n         state = 0\n         for i in s:\n             try:\n                 state = self.transition[state][key(i)]\n             except KeyError:\n                 return False\n         return state in self.final_states\n     \n     def isNumber_python(self, s):\n         try:\n             f = float(s)\n         except:\n             return False\n         else:\n             return True\n \n     def isNumber_manually(self, s):\n         \n         pass\n         \n'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'isNumber'
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: 47395