cs1520: lab 1
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1. Hello World
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write a small perl program to print "hello perl"


2. Fibonacci
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The Fibonacci sequence f(n) is defined as
	f(0) = 0
	f(1) = 1
	f(n) = f(n-1) + f(n-2)
Write a perl program to compute the nth fibonacci number.
Find f(73).
Find f(74).


3. Random Vacation Days 
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The cs department annual party will be held on a random
day of the week. To select the day, we will flip a 5-sided
coin 1000 times.

Use the following code to seed the PRNG and initialize a
hash table of counts:

@days = qw(mon tue wed thu fri);
%counts = map{ $_ => 0} @days;
srand(43);

Use the following to cast a float to an integer:

$myfloat = 5.5;
$myint = int($myfloat);

After 1000 coin flips, print the tally for each day.


4. K-Difference
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Create an array of integers using the following code:

$max = 1000000;
srand(2012);
for $i (0 .. $max) {
	@array[$i] = int(rand($max));
}

How many *unique* pairs of numbers have a difference of 2012?
That is, find the number of unique pairs (x,y) such that y - x = 2012.

What is the naive solution?
Can you think of a better solution whose time complexity is O(n)?