Code Room
CodingMedium
Question
Given an R x C integer matrix, an anti-diagonal is the set of cells (i, j) sharing the same value of i + j. Return a list giving the sum of each anti-diagonal, ordered from the top-left band (i+j = 0) through the bottom-right band (i+j = R+C-2). The matrix has at least one row and one column. Values may be negative.
Implement
diagonal_band_sums(grid: list[list[int]]) → list[int]Examples
in
[[[1,2,3],[4,5,6],[7,8,9]]]out[1,6,15,14,9]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.