This document provides tips and lessons learned from Soohan Ahn's experience interviewing for software engineering roles. It discusses resume screening, online coding assessments, project assignments, phone and online interviews, onsite interviews, and practice strategies. The key points are: practice coding problems extensively on sites like Codeforces and LeetCode; study STL containers and algorithms; implement sample projects; and use mock interviews to improve communication skills. While the process can be frustrating, with practice and experience, improvement and offers are possible.

1. Cracking the coding interview
Soohan Ahn
Freakout Inc
Failing

2. Survey

10. Resume Screening

11. 200+@
Applied

12. + Applied by the company website..
By the Linkedin...

13. Number of process to the next step?
10+@

16. Well..
Better than none

17. Check points
● Write a ‘hip’ resume.
○ Maybe, some recruiters would help you!

18. Check points
● Don’t waste time on the cover letter.

19. However...
VISA
WORK PERMIT

20. ● Citizen! Nationality.
● Or, Degree!
○ Funding….
Visa, Work permit

21. ● Japan, Singapore <<<< Australia,
Canada <<<<<<< US
Visa sponsorship difficulty (In my opinion..)

22. ● Possibility of relocation!
○ Indeed Tokyo -> Indeed US
○ Google Tokyo -> Google Palo Alto
○ Amazon Vancouver -> Amazon Seattle
○ etc..
Visa, Work permit

23. Online Coding Assesment

25. Invitement!

26. Online assesment platforms

27. Online assesment - 2018/01
● Codility
○ https://www.codility.com/
○ Failed….

28. Shocked…
End of the world...

29. Silicon Valley - HBO

30. Practice, Practice, Practice!!!!
● Codeforces
○ http://codeforces.com/

31. Practice, Practice, Practice!!!!

32. Practice, Practice, Practice!!!!
● Atcoder
○ https://atcoder.jp/

33. Difficulty
● Atcoder
○ Beginner contest: A,B,C
○ Reguler contest: A,B
● Codeforces
○ Div2: A,B,C

34. Online assesment - 2018/8
● Atcoder
○ Difficult..
○ 2/4 (50%) is enough.
○ Passed!

35. Online assesment - 2018/08
● Codility
○ Passed!

36. Online assesment - 2018/08
● Hackerrank
○ Passed!

37. Online assesment - 2018/11
● Hackerrank
○ Passed!

38. Project Assignments

39. Project assignment
● Implement simple project, and share
it to the private repository.

40. Project assignment - 2018/11
● A simple version of Imgur
● Floyd-warshall

41. Phone-Online interview

44. Online VS Phone - Onsite Interview
Online Phone, Onsite
Platform Programming platform Whiteboard, Text editor
Space complexity Not so important.. It is important!!!
Time complexity It matters.. It is important!!!
Mission Shut up and write down the code. Shut up and you fail!

45. Online Interview - 2018/8
● Casual tech talk.
○ Failed to review my resume well...
○ Failed....
○ Resume review is IMPORTANT!!

46. Online Interview - 2018/09
● Design a chatting app.
● Implement LRU Cache.

47. Online Interview - 2018/09

48. Practice, Practice, Practice!!!!

49. Practice, Practice, Practice!!!!

50. Practice, Practice, Practice!!!!

51. Practice, Practice, Practice!!!!
● Easy, Medium : Essential
● Hard: Popular problems.
○ LRU Cache

52. Online Interview - 2018/12
● Implement a random number distributor.
○ Std::vector::push_back…
● Should study STL, little bit deeper!

53. Online Interview - 2018/12

54. STL
● Standard template library for C++.
● JAVA: Collection (?)

55. Essential STL classes
● std::vector
○ Kind of array.
○ Using reserve makes better performance.
○ vector::push_back : Constant time.

56. Essential STL classes
● std::vector
○ https://en.cppreference.com/w/cpp/container/vector

57. Essential STL classes
● std::unordered_(map / set)
○ Hashmap.
○ Unsorted.

58. Essential STL classes
● std::map / set
○ Sorted hashmap.
○ http://www.cplusplus.com/reference/map/map/

59. Essential STL classes
● std::priority_quque
● std::stack
● std::queue
● std::list
● std::pair
● std::sort

60. Online Interview - 2018/11
● Simple algorithm questions.

61. Online Interview - 2018/12
● C++ and low-level questions.
● Failed. + No notice.

62. Online Interview - 2018/12
● Light tech talk.
● About an assignment.

63. Onsite Interview

64. Before jumping to the
onsite interview..

65. Online Interview - 2018/09
● Signed NDA…
● Problem was simple.
● Be careful at the simple problem!
○ Check requirements and the edge cases!

66. Online Interview - 2018/12
● 30 min tech talk.
● 1 algorithm problem

67. Onsite Interview - 2018/10

68. Onsite Interview - 2018/10
https://www.ana.co.jp

69. Onsite Interview - 2018/10

70. Onsite Interview - 2018/10
● Meal: $65/day
● Taxi: $100/day
● ETC: $45/day
○ Wifi router..

71. Onsite Interview - 2018/10
● Signed NDA…
● 60min X 5 + 60min lunch
○ 4 Engineers
○ 1 Product manager

72. Onsite Interview - 2018/10
● Each interview
○ 30 min behaviour.
○ 30 min coding interview

73. Onsite Interview - 2018/10

74. Onsite Interview - 2018/10

75. Onsite Interview - 2018/10
● Lack of the experience
○ Panic
○ Design problems(OOP, System)

76. Practice, Practice, Practice!!!!

77. Practice, Practice, Practice!!!!
● Not only solving lots of problem.
● Review, and make it perfect.
● Also, solve RELATED problems.

78. Practice, Practice, Practice!!!!

79. Practice, Practice, Practice!!!!

80. ● Write the simple code!
○ Less than 30 lines.
○ Make logics black box by functions!
○ In tree problem, implement by recursion!
○ Check other people’s optimized code!
Practice, Practice, Practice!!!!

81. Practice, Practice, Practice!!!!
● Peer mock interview platform!
○ I interview you, you interview me.
○ Not only interview prep, but English speaking!!

82. Onsite Interview - 2019/01
● 3 tech interviews.
● Got follow up problems. Solved well.

83. Offer

84. Offer!
But, declined..

85. Offer!

86. Excercises

87. LRU Cache
● https://leetcode.com/problems/lru-cache/

88. LRU Cache
● Hard to think about a implementation details during the interview.

89. LRU Cache
● Time complexity of std::list::erase?

90. LRU Cache
● Time complexity of std::list::erase?
○ https://en.cppreference.com/w/cpp/container/list/erase
Constant
O(last - first)

91. LRU Cache
● Deeper..
○ Implement a list class including an erase method.

92. LRU Cache
● Implement a list class including an erase method.
○ Need to know about a list structure!!

93. Lowest Common Ancestor of binary tree
● https://leetcode.com/problems/lowest-
common-ancestor-of-a-binary-
tree/description/
● Implement it recursively.

94. ● Implement it recursively.
Lowest Common Ancestor of binary tree

95. ● Implement it recursively.
Lowest Common Ancestor of binary tree
Time complexity: O(n)
Space complexity: O(1)

96. More problems
● 2sum
● Merge intervals
● Find the celebrity
● Valid parentheses

97. Wrap up

98. Wrapup
● Frustrating
● Tired
● Depressed
● Painful

99. Wrapup
● NOT FUCKING TALENTED.
● PRACTICE!

100. Wrapup
● Improvement!
● Offer

101. - Cao Hong (a.k.a 조홍)
Ref: 三國志 曹操伝 (KOEI)

102. “Practice, Practice, Practice!!!!”
- Soohan Ahn

103. Thanks!