Code RoomCombinations n choose k
MediumPrep Room Coding #4512

Combinations n choose k

CodingAlgorithms & data structuresMid–Senior~15 min

Return all combinations of k numbers chosen from the range 1..n, each combination as an ascending list, with the overall list sorted lexicographically. For k = 0 return a list containing one empty combination. 1 <= n <= 12, 0 <= k <= n.

Implement
combinations_nk(n: int, k: int) → list[list[int]]
Examples
in[4,2]out[[1,2],[1,3],[1,4],[2,3],[2,4],[3,4]]
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.

0:00 of about 15 min
InputExpectedGot
[4,2][[1,2],[1,3],[1,4],[2,3],[2,4],[3,4]]not run yetsample