Sorting coding problems

Sorting is often the step that makes a hard problem easy. Practise custom comparators, sorting by several keys, counting sort and the problems where sorted order reveals the answer.

36 problems: 15 easy, 20 medium, 1 hard. Free to read; a free account solves them and earns XP and Aura.

1. Count Distinct ElementsPractice · +10 XP · sorting, counting, arrayseasy
2. Count Pairs with Smaller SumPractice · +10 XP · two pointers, sorting, countingeasy
3. Find Second Largest ElementPractice · +10 XP · arrays, sorting, loopseasy
4. Find Second MinimumPractice · +10 XP · basics, sorting, conditionalseasy
5. Minimum Absolute DifferencePractice · +10 XP · greedy, sorting, arrayseasy
6. Minimum Cost to SortPractice · +10 XP · greedy, sorting, bubble sorteasy
7. Sort by Digit CountPractice · +10 XP · sorting, counting sort, custom ordereasy
8. Sort by Length and LexicographicallyPractice · +10 XP · sorting, stringseasy
9. Sort by Number of Set BitsPractice · +10 XP · sorting, counting sort, bit manipulationeasy
10. Sort by ParityPractice · +10 XP · sorting, custom ordereasy
11. Sort by Parity CountPractice · +10 XP · sorting, custom sortingeasy
12. Sort by Second DigitPractice · +10 XP · sorting, custom sorteasy
13. Sort Even and Odd NumbersPractice · +10 XP · sorting, basiceasy
14. Sort Students by ScorePractice · +10 XP · sorting, custom ordereasy
15. Top Three ScoresPractice · +10 XP · heaps, sorting, top-keasy
16. Count Unique Element PairsPractice · +20 XP · hash map, two pointers, sortingmedium
17. Group by PropertyPractice · +20 XP · hash map, grouping, sortingmedium
18. Maximize Non-overlapping IntervalsPractice · +20 XP · greedy, sortingmedium
19. Maximum Non-overlapping IntervalsPractice · +20 XP · greedy, sorting, intervalsmedium
20. Maximum Sum of Non-Overlapping SegmentsPractice · +20 XP · greedy, dynamic programming, sortingmedium
21. Merge Overlapping IntervalsPractice · +20 XP · sorting, intervalsmedium
22. Minimize Maximum DifferencePractice · +20 XP · binary search, greedy, sortingmedium
23. Minimize Maximum Difference in PairsPractice · +20 XP · greedy, sorting, two pointersmedium
24. Minimum Operations to Make Array SortedPractice · +20 XP · greedy, sorting, arraysmedium
25. Pairs with Same ParityPractice · +20 XP · sorting, two pointers, combinatoricsmedium
26. Sort by Custom PriorityPractice · +20 XP · sorting, custom sortingmedium
27. Sort by Digit DifferencePractice · +20 XP · sorting, custom sorting, sorting then scanningmedium
28. Sort by Digit GroupPractice · +20 XP · sorting, custom sorting, counting sortmedium
29. Sort by Digit ProductPractice · +20 XP · sorting, custom sorting, sorting then scanningmedium
30. Sort by Digit SumPractice · +20 XP · sorting, digit summedium
31. Sort by Group SumPractice · +20 XP · sorting, custom sorting, groupingmedium
32. Sort by Most Frequent DigitPractice · +20 XP · sorting, counting sortmedium
33. Sort by Relative OrderPractice · +20 XP · sorting, custom sortmedium
34. Sort by Subsequence SumPractice · +20 XP · sorting, hash map, prefix summedium
35. Sort Students by Two CriteriaPractice · +20 XP · sorting, stable sortmedium
36. Minimum Cost Path on a Grid with Custom Edge WeightsPractice · +30 XP · sorting, dijkstra, graphshard