Must-do problems: How to Approach a Problem

These problems practise the method from this module on small, realistic stories. For each one, restate it, trace the sample by hand, write down the edge cases, then check the limits to see whether a brute force is fast enough. Read the input the way a judge gives it, and compare your output with every test.

1. 1.Orders above the averageEasy
2. 2.Second largest markEasy
3. 3.Repeated customer idEasy
4. 4.Days without a weekly holidayEasy
5. 5.Ticket code reads the same both waysEasy
6. 6.Two orders that match a budgetMedium
7. 7.Best-selling productMedium
8. 8.Revenue between two daysMedium
9. 9.Longest streak of equal marksMedium
10. 10.First letter that appears onceMedium
11. 11.Smallest missing ticket numberMedium
12. 12.Best stretch of k daysHard
13. 13.Pairs with a fixed gapHard
14. 14.Longest word without a repeated letterHard
15. 15.Stretches that add up to zeroHard