Given an array of integers arr. Return the number of sub-arrays with odd sum.
As the answer may grow large, the answer must be computed modulo 10^9 + 7.
 
Example 1:
Input: arr = [1,3,5]
Output: 4
Explanation: All sub-arrays are [[1],[1,3],[1,3,5],[3],[3,5],[5]]
All sub-arrays sum are [1,4,9,3,8,5].
Odd sums are [1,9,3,5] so the answer is 4.

Example 2:
Input: arr = [2,4,6]
Output: 0
Explanation: All sub-arrays are [[2],[2,4],[2,4,6],[4],[4,6],[6]]
All sub-arrays sum are [2,6,12,4,10,6].
All sub-arrays have even sum and the answer is 0.

Example 3:
Input: arr = [1,2,3,4,5,6,7]
Output: 16

Example 4:
Input: arr = [100,100,99,99]
Output: 4

Example 5:
Input: arr = [7]
Output: 1

 
Constraints:

1 <= arr.length <= 10^5
1 <= arr[i] <= 100

```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 numOfSubarrays(self, arr: List[int]) -> int:\n        ans = 0\n        even_sums = []\n        odd_sums = []\n        current_sum = 0\n        for i in range(len(arr)):\n            current_sum += arr[i]\n            if current_sum % 2 == 0:\n                # is even\n                # if odd_sums[-1]\n                # if len(odd_sums) > 0:\n                #     ans += i - odd_sums[-1]\n                ans += len(odd_sums)\n                \n                even_sums.append(i)\n            else:\n                # is odd\n                # ans += 1\n                ans +=  1 + len(even_sums)\n                # j = 1\n                # while j <= len(even_sums) and even_sums[-j] == i-1\n                #     if \n                #     j += 1\n                # if len(even_sums) > 0 and even_sums[-1] == i-1:\n                #     ans += 1\n                # if len(odd_sums) > 0:\n                #     ans += i - odd_sums[-1] + 1\n                # else:\n                #     ans += i\n                # ans += len([]) \n                # last odd \n                # odd_sums[-1]\n                odd_sums.append(i)\n        return ans % (10**9 + 7)\n            \nif True:\n    print((Solution().numOfSubarrays([1,2,3,4,5,6,7]))) # 16\n    print((Solution().numOfSubarrays([100,100,99,99]))) # 4\n    print((Solution().numOfSubarrays([7]))) # 1\n    print((Solution().numOfSubarrays([2,4,6]))) # 0\n            \n        \n# [1,2,3,4,5,6,7]\n# [1]\n# [1,2]\n# [1]\n        \n# [1,3,5]\n# 1, 1, \n\n# [2,4,6]\n# 0\n\n# set(100), set(99), 200\n# [100,100,99,99]\n# 1 + 1 + 1\n\n# [1,2,3,4,5,6,7]\n# 1 + 1 + 1 + 1 set(1,3) set(2)\n'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'numOfSubarrays'
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: 5610