Count the turns — practice exercise

What you'll be asked to do

1. 1.Count the turnsexercise · easy · 10 min

   Count how many times the inner code runs for a 3 by 4 pair of loops.

   Passes when: #out should show 12.

2. 2.Add up a gridexercise · easy · 10 min · practice plan

   Add every number in the grid together and show the total.

   Passes when: #out should show 21.

3. 3.Build a star patternexercise · easy · 10 min · practice plan

   Build 3 rows of stars, where row 1 has one star. Join the rows with a dash.

   Passes when: #out should show *-**-***.

4. 4.Pair two listsexercise · easy · 10 min · practice plan

   Pair every name with every city and count how many pairs there are.

   Passes when: #out should show 6.

5. 5.Avoid repeating pairsexercise · medium · 10 min · practice plan

   Count each pair of numbers only once by starting the inner loop after the outer one.

   Passes when: #out should show 10.

6. 6.Fix the shared loop variablebug fix · easy · 8 min

   Both loops use i, so the inner loop overwrites the outer one.

   Passes when: #out should show 12.

7. 7.Fix the inner loop that never runsbug fix · easy · 8 min · practice plan

   The inner loop starts above its limit, so nothing is added.

   Passes when: #out should show 21.

8. 8.Fix the row that is never resetbug fix · easy · 8 min · practice plan

   The row string carries over, so every row keeps the stars before it.

   Passes when: #out should show *-**-***.

9. 9.Fix the break that stops too muchbug fix · easy · 8 min · practice plan

   A break in the inner loop was meant to skip, not to end the pairing early.

   Passes when: #out should show 6.

10. 10.Fix the repeated pairsbug fix · easy · 8 min · practice plan

    The inner loop starts at zero, so every pair is counted twice.

    Passes when: #out should show 10, not 20.

Between them these tasks cover Nested loops, Rows and columns and Two dimensional data.

Looking for a different chapter? See every practice set, or switch to the interview theory questions.