## 题目描述：

LeetCode 795. Number of Subarrays with Bounded Maximum

We are given an array `A` of positive integers, and two positive integers `L` and `R` (`L <= R`).

Return the number of (contiguous, non-empty) subarrays such that the value of the maximum array element in that subarray is at least `L` and at most `R`.

```Example :
Input:
A = [2, 1, 4, 3]
L = 2
R = 3
Output: 3
Explanation: There are three subarrays that meet the requirements: [2], [2, 1], [3].
```

Note:

• L, R  and `A[i]` will be an integer in the range `[0, 10^9]`.
• The length of `A` will be in the range of `[1, 50000]`.

## 解题思路：

```在A中找出所有大于R的整数，将这些整数消去，并将A分为若干个子数组

## Python代码：

``````class Solution(object):
def numSubarrayBoundedMax(self, A, L, R):
"""
:type A: List[int]
:type L: int
:type R: int
:rtype: int
"""
ans = lastIdx = 0
for i, x in enumerate(A + [10**10]):
if x > R:
ans += self.numSubarrayMinimumMax(A[lastIdx:i], L)
lastIdx = i + 1
return ans

def numSubarrayMinimumMax(self, A, L):
"""
:type A: List[int]
:type L: int
:rtype: int
"""
ans = lastIdx = 0
for i, x in enumerate(A):
if x >= L:
ans += (i - lastIdx + 1) * (len(A) - i)
lastIdx = i + 1
return ans
``````

Pingbacks已关闭。