The Third-Cheapest Price — medium Python for AI problem | Incognition

The Third-Cheapest Price

10 pts · 10 coins

Python for AIMedium

The Third-Cheapest Price

A price-comparison site has a list of prices for one product. The same price often appears more than once.

Task: write kth_cheapest(prices, k). Return the k-th cheapest different price.

k = 1 means the cheapest, k = 2 the next cheapest, and so on.
Repeated prices only count once: in [3, 3, 5], the 2nd cheapest is 5.
If there are fewer than k different prices, return None.

Examples

prices = [20, 15, 15, 30, 20, 25]

k = 3

returns 25

prices = [3, 3, 5]

k = 2

returns 5

prices = [9, 9, 9]

k = 2

returns None

Hints

solution.py

1def kth_cheapest(prices, k):
2    # your code here
3    pass
4