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Solution: Number of Valid Subarrays

Understand how to count subarrays whose first element is the smallest by applying a monotonic increasing stack approach. Learn to traverse the array while managing a stack to efficiently enumerate valid subarrays in linear time with optimal space. This lesson helps you grasp the solution to a common algorithmic problem useful for coding interviews.

Statement

Given an integer array nums, count how many non-empty contiguous subarrays exist where the first element of each subarray is less than or equal to every other element within that subarray.

Note: A subarray is defined as a contiguous portion of an array.

Constraints:

  • 11 \leq nums.length 1000\leq 1000

  • 00 \leq nums[i] ...