g0901_1000.s0907_sum_of_subarray_minimums

Class Solution

java.lang.Object

g0901_1000.s0907_sum_of_subarray_minimums.Solution

public class Solution
extends Object

907 - Sum of Subarray Minimums.

Medium

Given an array of integers arr, find the sum of min(b), where b ranges over every (contiguous) subarray of arr. Since the answer may be large, return the answer modulo 109 + 7.

Example 1:

Input: arr = [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.

Example 2:

Input: arr = [11,81,94,43,3]

Output: 444

Constraints:

• 1 <= arr.length <= 3 * 104
• 1 <= arr[i] <= 3 * 104

Constructor Summary

Constructors

Constructor and Description
Solution()

Method Summary

Modifier and Type	Method and Description
int	sumSubarrayMins(int[] arr)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Solution

public Solution()

Method Detail

sumSubarrayMins

public int sumSubarrayMins(int[] arr)