[Interview] Coding assessment
Brief
Example of backend software developer assessement test that can be completed within few hours.
It consists of few crucial points:
- API Generation
- Algorithmical work with geospatial data
- Caching strategy
Description
We have a database storing information about ATMs and their locations. Data structure is defined in the following format:
| Name | ID | Latitude | Longitude |
|---|---|---|---|
| VTB Mayakovskaya | VTB_M | 55.770935 | 37.596461 |
| Otkritie Yuzhnaya | OPEN_SOUTH | 55.621701 | 37.610418 |
| Sberbank Tverskaya | SBER_TVER | 55.763507 | 37.605967 |
| Pochta Marksistskaya | POCHTA_MARKS | 55.738556 | 37.661429 |
Goal
The task is to create an application with API of the following format
method: GET
path: /atms
params:
lat (float)
long (float)
rad (int)
response:
{
"data": [
{
"code": "VTB_M",
"name": "VTB Mayakovskaya",
"lat": 55.770935,
"long": 37.596461
},
...
]
}
Input:
- current coordinates of the client (lat, long)
- search radius (in meters)
The output shows the nearest ATMs in this radius.
Supplementary goal
Assume that access to ATM data source is an external call, with limit on number of requests.
Since ATMs are static and only the user’s position changes, a situation may arise when two users, not far from each, other make a request.
For each customer request, a cached response is required so that if another nearby customer makes a request, the response from the cache will follow instead of a new external request.