Code RoomOrders by customer and status
MediumPrep Room Coding #5035

Orders by customer and status

CodingAlgorithms & data structuresMid–Senior~10 min

Given `orders` with columns `order_id`, `customer`, `amount`, `status` and `placed`, count the orders for each `customer` and `status` pair. Return `customer`, `status` and `n`, sorted by `customer` ascending and then `status` ascending. Pairs that never occur do not appear.

Implement
status_counts(orders: dataframe) → dataframe
Examples
in[{"__df__":[{"amount":120.5,"placed":"2024-01-05","status":"paid","customer":"ada","order_id":1},{"amount":80,"placed":"2024-01-07","status":"refunded","customer":"bo","order_id":2},{"amount":45.25,"placed":"2024-02-11","status":"paid","customer":"ada","order_id":3},{"amount":200,"placed":"2024-02-14","status":"paid","customer":"cy","order_id":4},{"amount":15.75,"placed":"2024-03-02","status":"pending","customer":"bo","order_id":5},{"amount":60,"placed":"2024-03-19","status":"paid","customer":"ada","order_id":6}]}]out[{"n":3,"status":"paid","customer":"ada"},{"n":1,"status":"pending","customer":"bo"},{"n":1,"status":"refunded","customer":"bo"},{"n":1,"status":"paid","customer":"cy"}]
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 10 min
InputExpectedGot
[{"__df__":[{"amount":120.5,"placed":"2024-01-05","status":"paid","customer":"ada","order_id":1},{"amount":80,"placed":"2024-01-07","status":"refunded","customer":"bo","order_id":2},{"amount":45.25,"placed":"2024-02-11","status":"paid","customer":"ada","order_id":3},{"amount":200,"placed":"2024-02-14","status":"paid","customer":"cy","order_id":4},{"amount":15.75,"placed":"2024-03-02","status":"pending","customer":"bo","order_id":5},{"amount":60,"placed":"2024-03-19","status":"paid","customer":"ada","order_id":6}]}][{"n":3,"status":"paid","customer":"ada"},{"n":1,"status":"pending","customer":"bo"},{"n":1,"status":"refunded","customer":"bo"},{"n":1,"status":"paid","customer":"cy"}]not run yetsample