程序猿的自我修养清单

Data Structures
1. Integer

– find number of 1s

– next largest smaller

– smallest larger number

– determine if is palindrom

– itoa, atoi

– add 2 numbers w/o using + or arithmetic operators

– implement *, -, / using only +

– find max of two numbers w/o comparison

– swap two numbers with +/-

– swap two numbers with ^

– given an integer, find the closest number that is palindrome

– implement putlong() by putchar()

2. Bit array

3. Linked list

– find cycle,

– find position of cycle starts

– reverse LL

– delete a node in middle

– each node contains a value pointer pointing to a node,

duplicate LL.

– remove duplicates from sorted/un-sorted LL.

– find n-th to last node to end

– number is represented by LL, add 2 numbers

4. Array

– Longest common substring (LCSubstr)

– Longest common subsequence (LCS).

– Longest increasing subsequence (LIS).

– Longest palingdrome in string.

– array, elements are +/-, find subsequence of max sum

– circular array, elements are +/-, find subsequence of max sum

– find all pairs of integers add up to a sum

– find all pairs of integers add up to a sum,

integers are +/- and sorted

– find one missing number in N numbers in range [0, N]

– find two missing number in N numbers in range [0, N].

– binary search circular array

– Given {a1, a2, a3, ..}, {b1, b2, b3, …},

get {a1, b1, a2, b2, …}

– Given 2 arrays A and B, A large enough to hold both,

merge B into A.

5. String

– KMP, Rabin-Karp, Boyer Moore

– reverse string

– reverse words in string

– strcpy, strcmp, strstr, atoi, itoa, strdup

– remove duplicate characters in O(1) space

– Given dictionary, transform one word to another of same length.

– Given large text, find min cover distance of n words.

– find longest word made of other words

– find first non-repeated char

– remove specified char from a string

6. Matrix

– matrix elements are +/-, find submatrix of max sum

– rotate a matrix by 90 degrees

– each cell is black/white, find max subsquare with black border.

– binary matrix, find largest square matrix with 1s

– binary matrix, find largest rectangle matrix with 1s

7. Stack

– implement stack by queue.

– augmented stack with O(1) push, pop, min

– use single array to implement 3 stacks

– sort a stack in ascending order using only

push/pop/top/isEmpty/isFull

8. Queue

– implement queue by 2 stacks

9. Priority Queue

10. Heap

– create heap on array

11. Young Tableau

– find element

– get k-th element

12. BST

– pre/in/post-order traversal, recursive and iterative

– pre/in/post-order traversal, recursive and iterative,

with parent pointer

– find height

– determine IsBST

– find "next" node of a given node in inorder sequence

– find k-th inorder element

– find range of elements

– find diameter

– find all path adding to a sum

– Check if a tree is balanced

– Convert sorted array into balanced BST

– Find first common ancestor of two nodes in a BT or BST

– Link each node to its right sibling

– Print by level (BFS)

– Print by level (BFS) in reverse order

– Determine if 2 BSTs have the same structure

– Create a mirror BT of a BT

– Replicate a linked structure

13. 2-3-4 Tree

14. Red-Black Tree

15. Splay Tree

16. AVL Tree

17. Trie

18. Suffix Array

19. Suffix Tree

– LCSubstr (longest common substring)

– Longest repeated substring

– longest palindrome

– substring search

– data compression

20. B-Tree

21. KD Tree

22. Range Tree

23. Hash Table

24. Bloom filter

25. Disjoint set

26. Graph

– DFS, BFS

– find path existence between two nodes

– Min vertice set covering all edges

– shortest path

– minimum spanning tree

– min edge coverage by vertex
Sorting
1. Bubble sort

2. Insertion sort

3. Selection sort

4. Shell sort

5. Heap sort

6. Quick sort

7. Merge sort

8. N-way merge sort (external sort)

9. Counting sort

10. Bucket sort
Search
1. Linear search

2. Binary search

– Binary search, iterative/recursive

– find missing number is sorted array

– search in circular sorted array

3. Quick Select
Dynamic programming
1. BST

2. COV

3. ILP

4. KS

5. LCS

6. LSP

7. MCM

8. ODP

9. SCP

10. SPA

11. SPC

12. TSP

13. Given array a[], when i < j, get max(a[i] – a[j]).

14. levenshtein edit distance

15. Coin Change problem.
Large-scale system
1. Bloom filter

2. Bit-array/bit-map

3. Heap

4. Hash table

– d-left hashing

5. Sub-division

6. Database indexing

7. Inverted index

8. External sort

9. Map-reduce
Discrete math, Probability and Statistics, Numerical Computation
1. Permutation

– 3 colors, how many ways to color a cube?

– robot, ways to go to diagonal corner on NxN matrix?

– print all combinations of valid n-pairs of parentheses

– print all subsets of a set

2. Combination

3. Sampling

4. Random number generator

– What’s a good random number generator?

– Given random generator [1, 2, 3, 4, 5],

generate random in [1..7].

5. Reservoir sampling

6. Find median in stream

7. Card shuffling

8. Primality testing

9. Find prime numbers: naive, sieve of Eratosthenes, sieve of Atkin

10. Randomized primality testing, what’s good random generator

11. Fibonacci sequence

12. Factorial numbers

13. Frobenous numbers

14. Newton-Ralphson algorithm

15. Bayes theorem
Computational algebra
1. Convex-hull

2. Closest pairs
Computational theory
1. Automata theory

2. DFA

3. NFA

4. Regular language

5. Pumping lemma

6. Turing machine

7. NP-completeness

1. TSP

2. Vertex-cover problem

3. Set-covering problem.

4. Subset-sum problem.
OS
1. Process and thread

2. Semaphore, mutex, monitor

3. Function call/call frame

4. Context switch

5. Multi-threading

6. Multi-process

7. Thread safety

8. Big/Little-endian

9. Heap/stack

10. Malloc/free

11. Virtual memory, page fault, thrashing

12. DMA (Direct Memory Access)
Networking
1. 7-layer OSI model

2. 4-layer TCP/UDP model

3. TCP/UDP

4. TCP 3-way handshake (ACK machanism),

flow control, congestion control

5. Things happen after entering url

6. Routing protocols: BGP, OSPF, RIP

7. Subnet mask, packet routing on same/different network.

8. Performance
Database
1. Normalization

2. External sorting

3. B-tree, B+-tree.

4. Relational algebra
Compiler
1. LL, SLR, LALR, LR, GLR

2. recursive precedence

3. Operator precedence

4. Postfix evaluation of arithmetic expression

– implement a calculator
C/C++/Java
1. const char *, char * const, const char * const

2. static

3. volatile

4. explicit

5. Object/class

6. Inheritance

7. Encapsulation

8. Polymorphism

9. operator overloading

10. Composition/inheritance

11. Interface, abstract class

12. Struct/class

13. 4 default methods of a C++ struct/class

14. deep copy/shallow copy

15. C++ name hiding

16. C++ smart pointer

17. friend function/class

18. Multiple inheritance

19. Virtual inheritance

20. Constructor

21. Copy/assignment constructor

22. Virtual destructor

23. Virtual function, vtable

24. Pure virtual function

25. Macro, typedef, inline

26. C, C++, Java comparison

27. Garbage collection

28. Dangling pointer, free null pointer, memory leak

29. New/Delete

30. Malloc/free/realloc/calloc

31. Lock

32. Dead lock’s four conditions

33. #pragma directive

34. Exception handling

35. try/catch/finally

36. final, finally, finalize

37. Java object reflection

38. C++ templates, java generics

39. Effect of keeping constructor private

40. Pass by Value, reference, pointer

41. Reference v.s. pointer

42. In-memory file system data structures and algorithms?

43. Implement singleton

44. Implement singleton w/o static/global variable

45. Thread programming possible problems

46. sizeof operator.

47. Java: vector v.s. ArrayList

48. int (a*)[10]

49. Implement a lock.

50. Implement a buffer for DataOutputStream.

51. awk, tr, uniq, grep
Other problems
1. 2 eggs, 100 floors, find floor that breaks egg

minimizing number of drops.

2. 5 quart jug and 3 quart jug, measure 4 quarts of water.

3. 100 lockers, open every other i-th locker (i = 1, 2, …, 100).

Final open?

4. Men on island, can see hat on others only. N men, C hats,

days to remove?

5. 8/12 balls, find the one lighter/heavier

6. 8/12 balls, find one weighs different

7. 2 fuses each burns in 1 hour, measure 45 minutes

8. Bridge crossing, 1, 2, 5, 10. Minual number to pass bridge

9. Orange, apple, orange and apple, all labeled wrong. Find out.

10. 3 light switches, only one can be on at a time. Find it out.

11. Find the biggest, 2 biggest, biggest & smallest

12. n*m*k cube, how many are on the surface?

13. Test a pen, ATM machine, webpage, vending machine, program crash?

14. Given phone #, print all word representations on phone pad.

15. Find overlap of rectangles

16. Find median of two sorted arrays.

17. N computers each hold N numbers. Find median of these N*N numbers.

18. Recontruct a BT from pre/in/post-order traversal

19. Recontruct a BST from pre/in/post-order traversal

20. Find longest prefix common to all strings

21. Implement LRU cache system, O(1) find and update

22. Shifted sorted array, rotate.

23. Histogram, find max internal rectangle.

24. Tournament problem

25. N people, 1 celebrity, find celebrity in O(n) time.

26. 4 jars, 1 polluted so pills weigh +1, find out which jar

27. 25 horses, 5 horses maximal each match. Find the fastest 3

28. Mirror, why left/right reversed, not up/down?

29. How is next_permutation() in STL implemented?

30. N line segments on number axis, calculate common coverage

31. wild card match on patterns * (0-n) and ? (1).

32. Find number of trailing zeros in n!

33. Print square matrix in a spiral inwardly.

34. Find one’s phone number given resume only

35. N stairs, each time can go up 1 or 2. How many ways to go up?

36. Find majority element in an array.

37. Two cubes as a calendar

38. Coin change problem

39. Josephus Circle, last survivor?

40. Pick marbles, strategy to win?

41. Get sequence 1, 11, 21, 1211, …

42. C program that prints itself

43. Print week given date

44. enter code, allow one miss

45. Check equality of two number sets