Given s1, s2, s3, find whether s3 is formed by the interleaving of s1 and s2.

Example 1:


Input: s1 = "aabcc", s2 = "dbbca", s3 = "aadbbcbcac"
Output: true


Example 2:


Input: s1 = "aabcc", s2 = "dbbca", s3 = "aadbbbaccc"
Output: false

```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 isInterleave(self, s1, s2, s3):\n         """\n         :type s1: str\n         :type s2: str\n         :type s3: str\n         :rtype: bool\n         """\n         if len(s1) + len(s2) != len(s3):\n             return False\n         if not s1 and s2 and s3:\n             return True if s2 == s3 else False\n         if not s2 and s1 and s3:\n             return True if s1 == s3 else False\n         if not s1 and not s2 and not s3:\n             return True\n         if (s1 and s2 and not s3) or (not s1 and not s2 and s3):\n             return False\n \n         result = [[False] * (len(s2) + 1) for _ in range(len(s1) + 1)]\n         result[0][0] = True\n         for i in range(len(s1) + 1):\n             il_idx = i - 1\n             for j in range(len(s2) + 1):\n                 if i == j == 0:\n                     continue\n                 if j > len(s3) - 1:\n                     break\n                 s1_idx, s2_idx = i - 1, j - 1\n                 s1_char = s1[s1_idx] if s1_idx > -1 else None\n                 s2_char = s2[s2_idx] if s2_idx > -1 else None\n                 il_char = s3[il_idx + j]\n                 top = False if i == 0 else result[i - 1][j]\n                 left = False if j == 0 else result[i][j - 1]\n                 ds = set()\n                 if not left:\n                     ds.add(s1_char)\n                 if not top:\n                     ds.add(s2_char)\n                 result[i][j] = il_char in ds and (top or left)\n                 if (s1_char == s2_char == il_char) and top and left:\n                     result[i][j] = True\n                 #print(f" [{i},{j}] ==> checking if ** {il_char} **  in  {ds} ==> set result to {result[i][j]}")\n         #print(result)\n         return result[-1][-1]\n                 \n                 \n                 \n                 \n                 \n                 \n                 \n'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'isInterleave'
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: 6326