Beginner Coding Problems coding problems

New to coding problems? Start here: loops, conditions and simple input and output, the warm-ups that make the first round of a placement test feel easy.

60 problems: 58 easy, 0 medium, 2 hard. Free to read; a free account solves them and earns XP and Aura.

1. Alternating SumPractice · +10 XP · prefix sums, loops, basic arithmeticeasy
2. Count Black CellsPractice · +10 XP · matrix, traversal, beginnereasy
3. Count Character OccurrencesPractice · +10 XP · strings, loops, countingeasy
4. Count Consecutive OccurrencesPractice · +10 XP · dynamic programming, arrays, loopseasy
5. Count Digit SumPractice · +10 XP · strings, loops, parsingeasy
6. Count DivisorsPractice · +10 XP · basics, loops, arithmeticeasy
7. Count Elements Greater Than AveragePractice · +10 XP · basics, loops, arithmeticeasy
8. Count Elements Greater Than KPractice · +10 XP · hash map, counting, conditionalseasy
9. Count Elements Greater Than PreviousPractice · +10 XP · greedy, arrays, loopseasy
10. Count Equal NeighborsPractice · +10 XP · basics, arrays, loopseasy
11. Count Even NumbersPractice · +10 XP · basics, loops, conditionalseasy
12. Count Multiples of KPractice · +10 XP · dynamic programming, iteration, number theoryeasy
13. Count Non-Alphabetic CharactersPractice · +10 XP · strings, counting, loopseasy
14. Count Non-Positive NumbersPractice · +10 XP · basics, loops, conditionalseasy
15. Count Numbers Divisible by KPractice · +10 XP · dynamic programming, arrays, basic programmingeasy
16. Count Numbers with Even Set BitsPractice · +10 XP · bit manipulation, loops, countingeasy
17. Count occurrences of a numberPractice · +10 XP · basics, loops, arrayseasy
18. Count Occurrences of a Target ValuePractice · +10 XP · arrays, loops, countingeasy
19. Count Perfect SquaresPractice · +10 XP · math, loopseasy
20. Count Positive NumbersPractice · +10 XP · basics, loops, conditionaleasy
21. Count Set BitsPractice · +10 XP · bit manipulation, loops, basiceasy
22. Count Specific CharactersPractice · +10 XP · strings, counting, loopseasy
23. Count Uppercase LettersPractice · +10 XP · strings, loops, countingeasy
24. Count Vowel OccurrencesPractice · +10 XP · dynamic programming, strings, iterationeasy
25. Count Vowel PairsPractice · +10 XP · strings, loops, countingeasy
26. Find Second Largest ElementPractice · +10 XP · arrays, sorting, loopseasy
27. Find Second MinimumPractice · +10 XP · basics, sorting, conditionalseasy
28. Find Unset BitsPractice · +10 XP · bit manipulation, beginnereasy
29. First Occurrence of CharacterPractice · +10 XP · strings, string scanning, loopseasy
30. Matrix Element SumPractice · +10 XP · matrix, traversal, loopseasy
31. Matrix Row SumsPractice · +10 XP · matrix, loops, basiceasy
32. Maximum Odd SumPractice · +10 XP · greedy, iteration, basiceasy
33. Parity of Set BitsPractice · +10 XP · bit manipulation, loops, basiceasy
34. Print Array in ReversePractice · +10 XP · basics, arrayseasy
35. Print Digits of a NumberPractice · +10 XP · basics, loops, arithmeticeasy
36. Print Elements Larger Than PreviousPractice · +10 XP · stack, basic programming, iterationeasy
37. Print Nth Fibonacci NumberPractice · +10 XP · basics, loops, arithmeticeasy
38. Print Numbers in Reverse OrderPractice · +10 XP · recursion, arrays, iterationeasy
39. Print Queue ContentsPractice · +10 XP · queue, simulation, basic programmingeasy
40. Print Sum of DigitsPractice · +10 XP · dynamic programming, basic programmingeasy
41. Process First In First OutPractice · +10 XP · queue, simulation, beginnereasy
42. Reverse Array ElementsPractice · +10 XP · two pointers, array manipulation, beginnereasy
43. Reverse WordsPractice · +10 XP · strings, loops, simple parsingeasy
44. Simple Bracket CheckerPractice · +10 XP · stack, bracket matching, beginnereasy
45. Smallest ElementPractice · +10 XP · greedy, arrays, iterationeasy
46. Sort Even and Odd NumbersPractice · +10 XP · sorting, basiceasy
47. String Symmetry CheckPractice · +10 XP · strings, loops, conditionalseasy
48. Sum of Adjacent ElementsPractice · +10 XP · two pointers, arrays, loopseasy
49. Sum of Array ElementsPractice · +10 XP · recursion, arrays, iterationeasy
50. Sum of Even NumbersPractice · +10 XP · basics, loops, arithmeticeasy
51. Sum of Even-Indexed ElementsPractice · +10 XP · prefix sums, array manipulation, basic programmingeasy
52. Sum of First K MultiplesPractice · +10 XP · dynamic programming, arithmetic progression, iterationeasy
53. Sum of First N Even NumbersPractice · +10 XP · dynamic programming, iterationeasy
54. Sum of Multiples of Three and FivePractice · +10 XP · math, loops, divisibilityeasy
55. Sum of Odd DigitsPractice · +10 XP · math, digits, loopseasy
56. Sum of Positive NumbersPractice · +10 XP · greedy, loopseasy
57. The Polite WaiterDaily · +5 XP · +3 Aura (late, half) · strings, counting, loops1 solvedeasy
58. Unique NumberPractice · +10 XP · bit manipulation, xor tricks, beginnereasy
59. Longest Non-Decreasing SubsequencePractice · +30 XP · basics, dynamic programming, binary searchhard
60. Maximum Sum of Non-Adjacent ElementsPractice · +30 XP · basics, dynamic programming, arrayshard