Track a running maximum — practice exercise

What you'll be asked to do

1. 1.Track a running maximumexercise · easy · 10 min

   Walk the array once and show the largest value found.

   Passes when: #out should show nine.

2. 2.Sum in one passexercise · easy · 10 min · practice plan

   Add every value and show the total.

   Passes when: #out should show total 12.

3. 3.Remove zeros in placeexercise · easy · 10 min · practice plan

   Use read and write pointers to strip zeros, then join what remains.

   Passes when: #out should show 1-3.

4. 4.Walk from both endsexercise · easy · 10 min · practice plan

   Report whether the array reads the same forwards and backwards.

   Passes when: #out should show mirrored.

5. 5.Remember what you sawexercise · medium · 10 min · practice plan

   Use a Set to report the first value that repeats.

   Passes when: #out should show repeat is 2.

6. 6.Fix the maximum seeded with zerobug fix · easy · 8 min

   Starting at zero breaks when every value is negative.

   Passes when: #out should show minus two.

7. 7.Fix the write pointer never advancingbug fix · easy · 8 min · practice plan

   Without incrementing write, every kept value lands in slot zero.

   Passes when: #out should show 1-3.

8. 8.Fix the pointers moving the same waybug fix · medium · 8 min · practice plan

   Both pointers advance forwards, so every element is only ever compared with itself.

   Passes when: #out should show different.

9. 9.Fix the Set checked after addingbug fix · easy · 8 min · practice plan

   Adding before testing means every value looks like a repeat.

   Passes when: #out should show repeat is 2.

10. 10.Fix removal while looping forwardsbug fix · easy · 8 min · practice plan

    Splicing during a forward loop skips the element that shifts into place.

    Passes when: #out should show 1-3.

Between them these tasks cover Running state, Read and write pointers and Both ends.

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