PROBLEM STATEMENT
The output of a multithreaded system can be quite garbled, due to the interleaved execution that 
occurs.  In this problem, we will model such a situation.  Each thread's output will be described 
by a string.  For example, the string "AB" would mean that after 1 time unit running, the thread 
would print an 'A'.  After another time unit it would print a 'B'.  After a third time unit, it 
would print an 'A' (wraps back to the beginning).  You will be given a vector <string> describing 
the threads to be run.  You will also be given a vector <string> containing the time slices each 
thread is given.  Each element of slices will have the form "Thread# Time".  Thread# is a 0-based 
index into threads.  Time is how many units of time the thread in question will execute for.  The 
elements of slices occur in the order they will be run.  If a thread is executed, and then 
executed again at a later point, it starts where it left off (see examples for further 
clarification).

You will return a string containing the output in the order it occurred.  For example, if 
  threads = {"AB","CD"}
  slices = {"0 1","1 1","0 1","1 2"} 
Then you would return "ACBDC".  

DEFINITION
Class:PrintScheduler
Method:getOutput
Parameters:vector <string>, vector <string>
Returns:string
Method signature:string getOutput(vector <string> threads, vector <string> slices)


CONSTRAINTS
-threads will contain between 1 and 50 elements inclusive.
-Each element of threads will contain between 1 and 50 characters inclusive.
-Each character in each element of threads will be a capital letter.
-slices will contain between 1 and 50 elements inclusive.
-Each element of slices will have the form "Thread# Time".  Thread# will be an integer, without 
extra leading zeros, between 0 and k-1 inclusive, where k is the number of elements in threads.  
Time will be an integer, without leading zeros, between 1 and 50 inclusive.


EXAMPLES

0)
{"AB","CD"}
{"0 1","1 1","0 1","1 2"} 

Returns: "ACBDC"

From the problem statement.  The output occurs as follows:
  Thread 0 - Runs for 1 unit  - Outputs "A"
  Thread 1 - Runs for 1 unit  - Outputs "C"
  Thread 0 - Runs for 1 unit  - Outputs "B"
  Thread 1 - Runs for 2 units - Outputs "DC"

1)
{"ABCDE"}
{"0 20","0 21"}

Returns: "ABCDEABCDEABCDEABCDEABCDEABCDEABCDEABCDEA"

2 long time slices.

2)
{"A","B"}
{"1 10","0 1","1 10","0 2"}

Returns: "BBBBBBBBBBABBBBBBBBBBAA"

3)
{"A"}
{"0 1"}

Returns: "A"

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