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        # 这道题是hulu2019年网测第二题 改成了最大值。\n        # medium难度。除了暴力O(n**2) 对于每个i，右侧逐渐从i到n-1\n        # 更好的办法是单调栈或者dp 时间复杂度O(n)或者O(nlogn)\n        '''\n        # increasing stacks,注意是subarray问题，所以是连续的一部分\n        n = len(A)\n        mod = 10 ** 9 + 7\n        left, right = [0]*n, [0]*n\n        #left[i]表示A[i]左侧，严格大于的长度\n        #right[i]表示A[i]右侧，大于的长度\n        #为什么，因为担心遇到连续的重复例如2，5，4，4，6 ，因此可以去掉重复部分\n        #谨记，可重复出现的数组里，为了区分最小的数量，左右单调性要求不同\n        s1, s2 = [], []\n        for i in range(n):\n            count = 1\n            while s1 and s1[-1][0] > A[i]:\n                count += s1.pop()[1]\n            left[i] = count\n            s1.append([A[i],count])\n        for i in range(n)[::-1]:\n            count = 1\n            while s2 and s2[-1][0] >= A[i]:\n                count += s2.pop()[1]\n            right[i] = count\n            s2.append([A[i],count])\n        return sum(a*l*r for a,l,r in zip(A,left,right)) % mod\n        '''\n        res = 0\n        s = []  # 最小值就用单调递增栈，每一个加进来的栈都是区域最小的，因为最大的被pop了\n        # 递增栈的一个特点就是左右都用0最后栈会清空而且第一个0长期存在可以不用考虑stack空的问题\n        A = [0] + A + [0]  # 都是大于1的数字，找最小值0没关系，反正两侧而且可以抵消因为*0\n        for i, x in enumerate(A):\n            while s and A[s[-1]] > x:\n                j = s.pop()\n                k = s[-1]\n                res += A[j] * (i - j) * (j - k)\n            s.append(i)\n        return res % (10 ** 9 + 7)"
_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: 5734