CodingHardcod-g938

Subject Monotonic stackLevel Senior–Staff~35 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

Given an array of integers, consider every contiguous subarray and take its minimum element. Return the sum of all those subarray minimums, modulo 1000000007. The array has at most 30000 elements, each between 1 and 30000.

Implement

sum_subarray_mins(arr: list[int]) → int

Examples

in[[3,1,2,4]]out17

What a strong answer looks like

State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.

Learn the concepts

Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.

Run or narrate your approach, then ask the coach.