code interview yingcai xiao hari krishna bodicharla
TRANSCRIPT
Code Interview
Yingcai XiaoHari Krishna Bodicharla
Code Interview
• What is it?• Books• The process• The questions• How to prepare?
What is it?
• Code Interview: job interview involves designing and writing programs. (the contents relate to coding.)
Digital Interview
• Digital Interview: online interview, video interview. The format relates to digital media. Can be real-time or pre-recorded.
Digital Interview
"The Essential Digital Interview Handbook" by Paul J. Bailo
online interview,
good reference even for face-to-face interview.
Books on Code Interview (in Safari)
•"Ace the Programming Interview: 160 Questions and Answers for Success“by Edward Guiness
•"Programming Interviews Exposed: Secrets to Landing Your Next Job" by John Mongan; Eric Giguere; Noah Kindler
•"Coding Interviews: Questions, Analysis & Solutions" by Harry He
Books on Code Interview (not in Safari)
•"Cracking the Coding Interview: 150 Programming Interview Questions and Answers" by Gayle Laakmann McDowell
•"Cracking the C, C++, and Java Interview" by S G Ganesh
The Process
• Usually after HR screening interview• Or after a phone interview• Can be online (digital)• Or face-to-face• Usually one-on-one with your interviewer. • You may have something to write on.
The Process
• You will be asked to write some code. • May need to talk through the question first• May be in an actual programming language • May be as pseudo-code.
The Questions
Compare two integers without using any comparison
operators?
The Questions
Swap two integers without using a temp?
The Questions
Which one is faster?
int I, J = 8;I = 0.5 * J;I = J / 2;I = J >> 1;
• Array• Linked List• Array List• Hash Table• Queue• Stack• Tree• Graph
Data Structures
Why different data structures?• Use minimum space (Array).• Fast to retrieve (Array).• Easy to search (Array, Indexing / Hashing, Tree).• Easy to modify (Linked List).• Persistent. (IDs not Pointers/References)• Sharable over the Internet. (XML)• Reduce coding errors. (Padded Array)
Data Structures
Persistent. (IDs not Pointers/References)• There is no use to save pointers/references or transmit them over the Internet. • Serialization (memory automatically allocated during loading)• Use indexes to link data instead of pointers/references (indexed faceset)
Data Structures
INDEX LINKED DATA STRUCTURE
Data Structure for Graphics
and Visualization
SERIALIZATION OF OBJECTS
Serialization
• Converting an object into a form that can be persisted or transported.
• Save objects to permanent storages.• Sent over the network. • Pass on to another object.
Deserialization
• Converts a stream into an object.
Together, these processes allow data to be easily stored and transferred.
Requirements for Serialization To allow an object to be serializable:• In a serializable class, you must ensure that
every instance variable of the class is also serializable.
• The class must be visible at the point of serialization.
• All primitive types are serializable.
Sample Code for Serialization// serializable class
class SerializeEmployee
{
public:
char character;
unsigned int id;
// serializing method
void Serialize(::std::ostream &os);
//static deserializing method
static SerializeEmployee Deserialize(::std::istream &is);
};
void SerializeEmployee::Serialize(std::ostream &os)
{
if (os.good())
{
os.write((char*)&character, sizeof(character));
os.write((char*)&id, sizeof(id));
}
}
Sample Code for DeserializationSerializeEmployee SerializeEmployee::Deserialize(std::istream &is)
{
SerializeEmployee retval;
if (is.good())
{
is.read((char*)&retval.character, sizeof(retval.character));
is.read((char*)&retval.id, sizeof(retval.id));
}
if (is.fail()) {
throw ::std::runtime_error("failed to read full struct");
}
return retval;
}
Serialization References
1. http://en.wikipedia.org/wiki/Serialization
2. http://www.slideshare.net/imypraz/java-serialization-8916554?v=qf1&b=&from_search=8
3. http://www.stackoverflow.com/questions/5707835/having-trouble-serializing-binary-data-using-ifstream-and-ofstream
Sharable over the Internet. (XML)• Text based• User defined tags• No header• Inefficient
Data Structures
Reduce coding errors. (Padded Array)• Bounds checker• Use padding cells at the beginning or end of an array.• Error if the padding cells were written to.
Data Structures
Space Partitioning• Quad Tree (for rectangular shapes)• Triangulation (for irregular shapes)
Data Structures
• Bubble• Merge• Quick • Heap• Insertion
Sorting