Given an integer array arr, remove a subarray (can be empty) from arr such that the remaining elements in arr are non-decreasing.
A subarray is a contiguous subsequence of the array.
Return the length of the shortest subarray to remove.
 
Example 1:
Input: arr = [1,2,3,10,4,2,3,5]
Output: 3
Explanation: The shortest subarray we can remove is [10,4,2] of length 3. The remaining elements after that will be [1,2,3,3,5] which are sorted.
Another correct solution is to remove the subarray [3,10,4].
Example 2:
Input: arr = [5,4,3,2,1]
Output: 4
Explanation: Since the array is strictly decreasing, we can only keep a single element. Therefore we need to remove a subarray of length 4, either [5,4,3,2] or [4,3,2,1].

Example 3:
Input: arr = [1,2,3]
Output: 0
Explanation: The array is already non-decreasing. We do not need to remove any elements.

Example 4:
Input: arr = [1]
Output: 0

 
Constraints:

1 <= arr.length <= 10^5
0 <= arr[i] <= 10^9

```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 = 'from typing import List\n\n\nclass Solution:\n    def findLengthOfShortestSubarray(self, arr: List[int]) -> int:\n        # 1. formulate two non-decreasing arr\n        pre_len = 1\n        while pre_len < len(arr):\n            if arr[pre_len] < arr[pre_len - 1]:\n                break\n            pre_len += 1\n        arr_a = arr[:pre_len]\n        if len(arr_a) == len(arr):\n            return 0\n\n        arr_b = [arr[-1]]\n        for j in range(len(arr) - 2, -1, -1):\n            if arr[j] <= arr[j + 1]:\n                arr_b.insert(0, arr[j])\n            else:\n                break\n        # print(arr_a, arr_b)\n\n        # 2. Loop through arr_a to find the ans\n        ans = len(arr) - 1\n        for i in range(len(arr_a)):\n            j = self.binary_search(arr_b, arr_a[i])\n            cut_length = len(arr) - (i + 1) - (len(arr_b) - j)\n            ans = min(ans, cut_length)\n        ans = min(ans, len(arr) - len(arr_a))\n        ans = min(ans, len(arr) - len(arr_b))\n        return ans\n\n    # need to return the index i such that arr[i] >= num\n    def binary_search(self, arr, num):\n        low = 0\n        high = len(arr) - 1\n        ans = len(arr)\n        while low <= high:\n            mid = (low + high) // 2\n            if arr[mid] >= num:\n                ans = min(ans, mid)\n                high = mid - 1\n            else:\n                low = mid + 1\n        return ans\n\n\n# leetcode submit region end(Prohibit modification and deletion)\n\ndef __starting_point():\n    solution = Solution()\n    assert (solution.findLengthOfShortestSubarray([1, 2, 3, 10, 4, 2, 3, 5]) == 3)\n    assert (solution.findLengthOfShortestSubarray([5, 4, 3, 2, 1]) == 4)\n    assert (solution.findLengthOfShortestSubarray([1, 2, 3]) == 0)\n    assert (solution.findLengthOfShortestSubarray([13, 0, 14, 7, 18, 18, 18, 16, 8, 15, 20]) == 8)\n    assert (solution.findLengthOfShortestSubarray([16, 10, 0, 3, 22, 1, 14, 7, 1, 12, 15]) == 8)\n\n__starting_point()'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'findLengthOfShortestSubarray'
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: 6374