Contiguous sum divisible by k
Given an integer array and an integer k, return the number of contiguous subarrays whose sum is divisible by k. The array has at most 30000 elements with values in [-10000, 10000]; k is a positive integer up to 10000. Note that negative prefix sums must be handled with care for the modulo.
Implement
subarrays_div_by_k(arr: list[int], k: int) → intExamples
in
[[4,5,0,-2,-3,1],5]out7What 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.
0:00 of about 25 min
solution.py
InputExpectedGot
[[4,5,0,-2,-3,1],5]7not run yetsample