This past spring, I spent 5 months or so (20 weeks) training for my first-ever marathon. I'm a college student, so this experience was simultaneously a huge gift and a huge pain. It was amazing for a bunch of reasons, but one of my favorite things was that it was a time of significant personal growth. It's incredible how much strength it takes to keep running when your body is exhausted and pained. It can really shape you. For example, that endurance spilled over into my academic work. Because I had trained my mind and body to keep pushing through exhaustion, I found my mind persisting through my schoolwork with the same determination. I attribute my success this past semester to this persistence.
I also loved that I didn't have to think about going to the gym. I'm the kind of person who always wants to go, but can't always bring myself to go running or lifting. I even loved miles 14-18 on my long runs, because my body would be in a completely different state of being that only endurance running could bring it to.
On the downside, training was tough on my social life at some points. I felt disconnected in a way, especially when I would have to go to bed early on a Saturday night. However, I thought it would be more difficult to drag myself out of my dorm to go on long runs on Sunday mornings - but actually I found it (mentally) easier to do 16-20 milers than the 6-10 milers. All in all, I'm so glad I had this experience - it's definitely going to be something I'm grateful for for the rest of my life.
I remember this one day, I had just begun my run, and I was about to descend down this pretty grueling hill. A few other runners were passing me, chugging up that incline, and I (in my instinctive way) tried to make eye contact with each one. While the majority just stared straight ahead, focal point on the top of that hill - understandable - one man connected with me. I smiled, he smiled, and then he gave me the thumbs-up. The thumbs-up. Why it charged me with such a wave of endorphins and positive energy I'm not entirely sure, but it stuck with me. Ever since then, I've always made a point to do the same for the other friendly runners I encounter out there. I don't know what you would call it, but it's possibly the best thing that has happened to me since Kinesio Tape and GPS run trackers.
Review some basic algorithms. If you need some inspiration, you can visit Top Coder and check out their tutorials. In fact, Google refers their interviewees to this site for practice. Also consider mastering some basic algorithms, such as the Greatest Common Denominator (GCD) algorithm and some sorting algorithms (especially either selection/insertion sort and merge sort, as the first two are easier but merge sort is faster). Finally, knowing some tree traversal algorithms (or at least the difference between breadth-first and depth-first traversal/post-order, in-order, and pre-order) would never hurt.
Review important key words and operators of the language you'll be programming in. For example, you should know about the bitwise operators and what they do, or (in python) how to make a list versus a dictionary. A list of Java keywords can be found here and a list of Python keywords can be found here (note: these are for version 2, not version 3).
While much of my blog is about computer science and running, I also consider this a space to write down my thoughts. Currently, I'm thinking a lot about study abroad options for next year. I'm fortunate enough to go to a school with amazing connections world wide, where it is seemingly the norm for students to study abroad in a different country for part of their Junior year. In fact, staying at school for your entire Junior year is often referred to as "JY-Stay". So I've always thought I'd go abroad for at least a semester, but now I'm not so sure. Here are some of my concerns:
First of all, being a computer science major abroad is difficult. Few programs that I'm interested in allow visiting students to study CS for only one American semester, which is a bummer because I am not interested in going abroad for a year.
Second, as my father and friends have pointed out, going abroad should be about the experience abroad - therefore, I don't want to go overseas to some country I don't care much for (i.e. Hungary - Budapest has a great CS program, but I just am not interested in spending a semester there). I really am only interested in going to England, as dull as that sounds, because my mom grew up there and a lot of my heritage traces back to the UK. However, I don't just want to go anywhere in England - I'm particularly fond of London, Oxford and Cambridge.
Third, the dates are kind of screwy. If I want to have another internship during the summer after my Junior year (which I definitely do, whether that be at Google or Microsoft, or a Boston start up company), I need to allot more or less 12 weeks for it. However, if I do one of these programs in England, the "Summer" term (exams and whatnot) will last at a minimum until June 12th-ish. That means that I'd be working until the day school starts, and I'm not sure if that's going to be an option.
Fourth, a ton of my friends and my girlfriend will be seniors, and I'll miss everything they'll be doing: Senior Ball, Senior Week, Senior Banquet, and graduation, to name a few. That would make me sad.
Fifth, what I realized is that I'm actually really interested in the British culture and travelling around Europe. This is another reason why going abroad to another country might not be in line with my interests, but it also suggests that maybe a Euro-trip would be more up my alley than an entire Semester abroad...
But I also have concerns about not going... like regretting it later, or not getting an awesome chance to study in England. Or what if I'm being narrow-minded in only considering England? What if Australia or some other European country would be just as awesome? Is study abroad truly an experience I could never replicate, or is just an experience others feel that they could never replicate (if they study in Spain or Italy, for instance)? Would I be fulfilled by just visiting England for a few weeks? Or do I need an entire semester to have the experience I want?
I'll be visiting the study abroad office as soon as I get back to school, but I've had these concerns floating around in my head for several days now and I wanted to write them down. I'm not distraught over them, just conflicted. This is such an amazing opportunity, and I don't want to waste it. However, I'm not sure that I should take it just because it's there... no one else in my family has studied abroad, and they've lived lives full of travel and fulfillment. So it's not like it's now or never. Still, though, I don't want to miss out if this truly is worth it. I guess I'll have to see.
Do not just reread your old data structures code, nod your head, and tell yourself you understand it. Recode it! It takes maybe half an hour tops to rewrite a basic implementation of a binary tree, and, even if you know trees like the back of your hand, it will never hurt to redo it. In the first tip I mentioned being able to BS better if you studied your definitions and implementations. Recoding will remind you of some of the little details (for example, the fact that stacks and queues are interfaces, so you need to implement those interfaces if you are coding class implementations...).
Study at least a little bit (1-2 hours is ideal) every day for the two weeks before your interview. If your interview is scheduled less than two weeks in advance, then start ASAP. Or if you know that you're going to be interviewing soon, start right now. It never hurts to begin reviewing your basic data structure definitions and implementations, because you can be almost certain that you will be tested on them in many ways. So starting early = acing that quiz, or at least being able to BS better if you get completely lost.
So I recently applied for internships with some cool tech companies, and ended up landing a place in Google's Sophomore Engineering Practicum for next summer. I'm absolutely stoked! But, looking back on the process, I know I felt like I had very little idea of what to expect. I hard core stalked any blog I could find on the matter, and only a couple (especially http://ecarmi.org/writing/google-internship/) actually satisfied my curiosity. So I'm hoping to shed a little bit of light on how to prepare for the process.
I've decided to post a series of programming interview tips (of which this is the intro... duh), and I hope they help. I aim for these posts to be short, sweet, and hopefully to the (helpful) point. Disclaimer: I am only a sophomore in college, so my prep was probably (er, definitely) not as extensive as it needs to be for a job interview, or even for other internships. So just look at this as a starting point :)
My last posts covered some of the fundamentals of programming. This one is going to tackle something slightly more advanced: linked lists.
A linked list is useful because it is, in essence, a resizable array. The idea of a linked list is to have each element, called a node, have a "next" (and, in our/most cases, "previous") pointer. The first element in the list is called the head and the last element is sometimes called the tail, but I won't include a tail in my implementation. There are various ways to implement this, but I'm going to start with a basic linked list and then move on to some of the more tricked-out variations in other posts.
I'm going to write this in Python, even though Python has built in lists that are really powerful, because I've never done a linked list implementation in Python before. Here we go:
The header and code for Node:
#LinkedList.py #J.B.E. #computationaltheory.tumblr.com #January 11, 2013 # # This program contains two classes: one for a simple Node (for a # linked list), and another for the simple linked list implementation. # # Methods: # # NODE: # # __init__: constructor. Must provide a value, but, if left # unspecified, next and prev are set to None. # getNext(): returns the Node's next neighbor # getPrev(): returns the Node's previous neighbor # getValue(): returns this Node's value # setValue(val): set this Node's value # setNext(val): set the Node's next neighbor # setPrev(val): set the Node's previous neighbor # # LINKED LIST: # # __init__: constructor, creates empty list # addLast(val): add a new node to the end of the list # addFirst(val): add a new node to the beginning of the list # insert(val, index): insert a new node at the specified index # (if no index is given, same as addFirst) # getSize(): returns the number of elements in the list # printList(): prints out the value of the elements in the # list, separated by a few spaces class Node: def __init__(self, value, next=None, prev=None): self.value = value self.next = next self.prev = prev def getNext(self): return(self.next) def getPrev(self): return(self.prev) def getValue(self): return(self.value) def setValue(self, value): self.value = value def setNext(self, node): self.next = node def setPrev(self, node): self.prev = node
and the code for Linked List:
class LinkedList: def __init__(self): #create an empty list or a list with one element self.head = None self.size = 0 def addLast(self, value): if(self.head==None): self.head = Node(value) else: node = self.head while(node.getNext()!=None): node = node.getNext() node.setNext(Node(value, None, node)) self.size+=1 def addFirst(self, value): oldHead = self.head self.head = Node(value, oldHead) if(oldHead!=None): oldHead.setPrev(self.head) self.size+=1 def insert(self, value, index=0): if(index>self.size or index < 0): print("Index out of range!") return elif(index==(self.size)): self.addLast(value) elif(index==0): self.addFirst(value) else: targetNode = self.head for i in range(index): targetNode = targetNode.getNext() prevNode = targetNode.getPrev() newNode = Node(value, targetNode, prevNode) prevNode.setNext(newNode) targetNode.setPrev(newNode) self.size+=1 def getSize(self): return (self.size) def printList(self): node = self.head if(self.head==None): print("This list is empty.") else: while(node!=None): print(node.getValue(), end=" ") node = node.getNext()
And that's it! There might be some bugs, but I tried to test a bunch of different cases and it seemed to work for all of them. If you see anything, feel free to leave a comment for me below! Happy coding!
For all those programmers out there who want to familiarize yourself with common interview questions, check out this YouTube account! It covers a lot of really useful, cool stuff. Or if you just want some new challenges, this is a great place to find them.
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