四岁小孩Ipad app 推荐# Parenting - 为人父母
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从6月初开始准备找工作，找了近半年，期间毁onsite无数，最近终于有所收获，拿到
几个offer，虽然不是那几个著名大公司，不能和版上的牛人比，但也算和自己专业相
近，决定挑一个从了。穷人没什么包子，就说点感想发点面经，答谢本版。顺便求祝福
接下来的process能够顺利。今年h1b已经用完了，我是打算quit phd做full time的，
学校的CPT/OPT没过qualify之前还不让full time，庆幸公司允许我先做part time。希
望一切能够顺利。也bless其他找工作的同志们。
1. 找工作还是要花大量时间精力充分准备的，各种基本概念、data structure,
algorithms, programming language concepts，还有自己简历上写的各种project要把
每个细节都弄清楚。没准备好之前不要轻易投大公司浪费机会，免得追悔莫及。我就有
惨痛的教训。一下是我主要复习的材料。
career cup
programming interview expose
ihas1337code
thecareerplus
geeks for geeks
thinking in java
C++ interview questions
Introduction to algorithms
编程之美
版上面经
2. 一定要坚信自己能找到一份工作，即使在最沮丧失落的时候，也要相信有一份适合
的工作在等自己。只要花时间肯努力，我周围没有听说谁努力找不到工作的，即使
background再弱，经验再少，技术再差，也能通过努力提高。很多时候不是自己不够好
，只是职位不适合而已。
3. 面试前要对公司的project了解一下，这样在聊的时候就有针对性，别人也会觉得你
有相关的知识和经验。就算某些方面不懂，也要尽量扯一些以前相关的经历，并表达自
己open to different roles的诚意。
4. 微笑，再微笑，且直视对方。微笑能缓解很多问题答不上来的尴尬，也显示你的自
信和好的personality。很多时候性格比技术更重要。
就想到这么多，先写这些。下面是一些phone和onsite被问到的问题，我把他们整理成3
个部分，有一些重复的，也有一些本版没见过的，或者和OS system相关的，仅供参考
。公司名就不一一列了，有A M G，一些system相关的公司和一般的software company。
Basic concepts：
1. what’s link list, array, hashtable, search/create time complexity
2. How to implement a hashtable, how to solve collision problems
3. The difference between List, Set, and Map in Java
4. Interface, abstract class
Coding：
1. Find duplicate elements in two arrays
2. Determine what a system is big- or little- endian
3. reverse a string
4. Design a timing mechanism: when a packet is received, cancel the timing;
otherwise, start timing until time out. Suppose each timing object has
different expiration period?
5. Given an integer, print out its square root
6. An integer array of size m + 1 with m unique element, find the duplicate
one
7. Given a function to read/write data from/to hard disk. Req(r/w, addr,
size, buffer), e.g.Read_write(read, 0, 5, …), Read_write(read, 5, 3, …).
This function will be called thousand times. Consolidate the I/O requests
and printout to one.
“read command, start from address 0, access 8 sectors.”
8. 输入一串整数数列， 求里面连续的可构成等差数列的sub-array的个数（>=3）
e.g. [1, 2, 3, 5, 7, 9, 8, 7];
output should be : 5
[1, 2, 3] [3, 5, 7] [3, 5, 7, 9][5, 7, 9] [9, 8, 7]
Time complexity O(n), space complexity O(1)
9. Print a two dimensional array clockwise
10. N*M grid, walk from (0,0) to (n, m), either 'right' or 'down', return
the number of possible paths; There might be some obstacles in the grid.
11. Two integers n & m represented as two arrays, return n*m in terms of one
array
12. An array(0, 2, 1, 0, 2, 1, ...), only three different values, sort in
place
13. Print all combinations of an input array, if there are duplicates, e.g.
(1, 2, 2, 3), output: 1, 12, 122, 123, 1223, …
14. Count the palindrome in a string
15. Given two XML, check whether they are equivalent
16. Career cup: 19.6, print the English phrase of an integer
17. Describe a data structure to store a tree node, if a tree node has a
pointer to the sibling, write a function to update the sibling (level-order
traverse)
18. Mth to the last node in a link list (be careful about m & m-1)
19. Design a calculator: overflow, -error-, function test
20. Atoi
21. Write a singleton pattern
22. Find overlap between two sets of pairs
23. 1TB file that can not fit into memory, how to rotate the lines randomly
and write to a new file? How to deal with it in distributed systems? How to
detect one node's failure?
24. runlength encoded: [number of next elem in the array, the value of the
elem]
2, 1, 3, 6, 1, 9 => 1, 1, 6, 6, 6, 9
Create a class and implement the following two methods:
getNext()
hasNext()
25. Determine whether two words are anagram, how to do pre-processing for a
dictionary, so that it could do fast anagram searching
26. Suppose we can compare two arrays like:
{4,2,3} > {3,5,6}
{4,2,3} < {4,3,0}
In each move, you can only swap a number with its neighbor. Given an array
and a number n, design an algorithm to make this array minimum using n moves.
27. Find the second largest number in an array
28. Design a restaurant booking system
System related：
1. what is race condition
2. what is deadlock, how to detect deadlock
3. what’s kmalloc
4. what happens when an application generates a request, what happen to
system call, why using system call, how data transfers between user and
kernel level
5. process vs. threads, address space, etc
6. How a process is created, how to do mapping between virtual address and
physical memory
7. heap vs. stack
8. condition variable
9. what's the data flow from OS -> device
10. how to detect memory leak
11. single writer, multi-reader lock problem
12. How linux command 'ls' works
13. spin_lock, mutex, semaphore
14. POSIX interface: sockets mode(blocking vs. nonblocking)
15. The cause of segmentation fault
几个offer，虽然不是那几个著名大公司，不能和版上的牛人比，但也算和自己专业相
近，决定挑一个从了。穷人没什么包子，就说点感想发点面经，答谢本版。顺便求祝福
接下来的process能够顺利。今年h1b已经用完了，我是打算quit phd做full time的，
学校的CPT/OPT没过qualify之前还不让full time，庆幸公司允许我先做part time。希
望一切能够顺利。也bless其他找工作的同志们。
1. 找工作还是要花大量时间精力充分准备的，各种基本概念、data structure,
algorithms, programming language concepts，还有自己简历上写的各种project要把
每个细节都弄清楚。没准备好之前不要轻易投大公司浪费机会，免得追悔莫及。我就有
惨痛的教训。一下是我主要复习的材料。
career cup
programming interview expose
ihas1337code
thecareerplus
geeks for geeks
thinking in java
C++ interview questions
Introduction to algorithms
编程之美
版上面经
2. 一定要坚信自己能找到一份工作，即使在最沮丧失落的时候，也要相信有一份适合
的工作在等自己。只要花时间肯努力，我周围没有听说谁努力找不到工作的，即使
background再弱，经验再少，技术再差，也能通过努力提高。很多时候不是自己不够好
，只是职位不适合而已。
3. 面试前要对公司的project了解一下，这样在聊的时候就有针对性，别人也会觉得你
有相关的知识和经验。就算某些方面不懂，也要尽量扯一些以前相关的经历，并表达自
己open to different roles的诚意。
4. 微笑，再微笑，且直视对方。微笑能缓解很多问题答不上来的尴尬，也显示你的自
信和好的personality。很多时候性格比技术更重要。
就想到这么多，先写这些。下面是一些phone和onsite被问到的问题，我把他们整理成3
个部分，有一些重复的，也有一些本版没见过的，或者和OS system相关的，仅供参考
。公司名就不一一列了，有A M G，一些system相关的公司和一般的software company。
Basic concepts：
1. what’s link list, array, hashtable, search/create time complexity
2. How to implement a hashtable, how to solve collision problems
3. The difference between List, Set, and Map in Java
4. Interface, abstract class
Coding：
1. Find duplicate elements in two arrays
2. Determine what a system is big- or little- endian
3. reverse a string
4. Design a timing mechanism: when a packet is received, cancel the timing;
otherwise, start timing until time out. Suppose each timing object has
different expiration period?
5. Given an integer, print out its square root
6. An integer array of size m + 1 with m unique element, find the duplicate
one
7. Given a function to read/write data from/to hard disk. Req(r/w, addr,
size, buffer), e.g.Read_write(read, 0, 5, …), Read_write(read, 5, 3, …).
This function will be called thousand times. Consolidate the I/O requests
and printout to one.
“read command, start from address 0, access 8 sectors.”
8. 输入一串整数数列， 求里面连续的可构成等差数列的sub-array的个数（>=3）
e.g. [1, 2, 3, 5, 7, 9, 8, 7];
output should be : 5
[1, 2, 3] [3, 5, 7] [3, 5, 7, 9][5, 7, 9] [9, 8, 7]
Time complexity O(n), space complexity O(1)
9. Print a two dimensional array clockwise
10. N*M grid, walk from (0,0) to (n, m), either 'right' or 'down', return
the number of possible paths; There might be some obstacles in the grid.
11. Two integers n & m represented as two arrays, return n*m in terms of one
array
12. An array(0, 2, 1, 0, 2, 1, ...), only three different values, sort in
place
13. Print all combinations of an input array, if there are duplicates, e.g.
(1, 2, 2, 3), output: 1, 12, 122, 123, 1223, …
14. Count the palindrome in a string
15. Given two XML, check whether they are equivalent
16. Career cup: 19.6, print the English phrase of an integer
17. Describe a data structure to store a tree node, if a tree node has a
pointer to the sibling, write a function to update the sibling (level-order
traverse)
18. Mth to the last node in a link list (be careful about m & m-1)
19. Design a calculator: overflow, -error-, function test
20. Atoi
21. Write a singleton pattern
22. Find overlap between two sets of pairs
23. 1TB file that can not fit into memory, how to rotate the lines randomly
and write to a new file? How to deal with it in distributed systems? How to
detect one node's failure?
24. runlength encoded: [number of next elem in the array, the value of the
elem]
2, 1, 3, 6, 1, 9 => 1, 1, 6, 6, 6, 9
Create a class and implement the following two methods:
getNext()
hasNext()
25. Determine whether two words are anagram, how to do pre-processing for a
dictionary, so that it could do fast anagram searching
26. Suppose we can compare two arrays like:
{4,2,3} > {3,5,6}
{4,2,3} < {4,3,0}
In each move, you can only swap a number with its neighbor. Given an array
and a number n, design an algorithm to make this array minimum using n moves.
27. Find the second largest number in an array
28. Design a restaurant booking system
System related：
1. what is race condition
2. what is deadlock, how to detect deadlock
3. what’s kmalloc
4. what happens when an application generates a request, what happen to
system call, why using system call, how data transfers between user and
kernel level
5. process vs. threads, address space, etc
6. How a process is created, how to do mapping between virtual address and
physical memory
7. heap vs. stack
8. condition variable
9. what's the data flow from OS -> device
10. how to detect memory leak
11. single writer, multi-reader lock problem
12. How linux command 'ls' works
13. spin_lock, mutex, semaphore
14. POSIX interface: sockets mode(blocking vs. nonblocking)
15. The cause of segmentation fault
