Given an array of integers A, find the sum of min(B), where B ranges over every (contiguous) subarray of A.
Since the answer may be large, return the answer modulo 10^9 + 7.
 
Example 1:
Input: [3,1,2,4]
Output: 17
Explanation: Subarrays are [3], [1], [2], [4], [3,1], [1,2], [2,4], [3,1,2], [1,2,4], [3,1,2,4]. 
Minimums are 3, 1, 2, 4, 1, 1, 2, 1, 1, 1.  Sum is 17.
 
Note:

1 <= A.length <= 30000
1 <= A[i] <= 30000

```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 sumSubarrayMins(self, A: List[int]) -> int:\n        def right_boundry(A, dupl):\n            res = [0] * len(A)\n            A.append(-math.inf)\n            stack = []\n            \n            for i in range(len(A)):\n                if dupl:\n                    while stack and A[stack[-1]] >  A[i]:\n                        j = stack.pop()\n                        res[j] = i - j\n                else:\n                    while stack and A[stack[-1]] >=  A[i]:\n                        j = stack.pop()\n                        res[j] = i - j\n                    \n                stack.append(i)\n            \n            A.pop()\n            return res\n        \n        right = right_boundry(A, False)\n        left = right_boundry(A[::-1], True)[::-1]\n        \n        ans = sum([right[i]*left[i]*A[i] for i in range(len(A))]) \n        \n        return ans %(10**9+7)\n\n    \n#         dp = [0] * (len(A) + 1)\n#         N = len(A)\n        \n#         for i in range(1,N+1):\n#             mn = A[i-1]\n#             dp[i] = dp[i-1]\n#             for j in range(i, 0, -1):\n#                 mn = min(mn, A[j-1])\n#                 dp[i] = (dp[i] + mn) % (10**9 + 7)\n        \n#         return dp[-1]\n        \n        \n#         cnt = 0\n#         k = 1\n        \n#         while k <= len(A):\n#             stack = []\n#             for i in A:\n#                 if len(stack) < k: \n#                     stack.append(i)\n#                     if len(stack) == k:\n#                         cnt += min(stack)\n#                         stack.pop(0)\n                        \n#             k += 1\n            \n#         return cnt\n                    \n'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'sumSubarrayMins'
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: 6688