2021-10-12

Eight before nine in a list.

Warmup: count the number of times that an 8 comes before a 9 in a list of integers.

  • Basic: count one for every 8 that comes immediately before a 9.

  • Advanced: count one for every time there is a 9 somewhere after an 8, giving two for this example:

      [8,1,1,1,9,8,9]
    

Class notes

If the problem is phrased “count the number of times a 9 comes after an 8”, then I would count two for either of these examples:

[8,9,9]
[8,8,9,8,9]
Last modified August 18, 2023: 2022-2023 End State (7352e87)