Modify README to reflect the most recent changes

Author: seanchen1991

README.md

@@ -9,20 +9,22 @@ For the algorithms portion of the sprint challenge, you'll be answering the ques
 ### Task 1. Implement Depth-First and Breadth-First Traversal on the Binary Search Tree Class 
 Navigate into the `ex_1` directory in the `data_structures` directory. Inside, you'll see the `binary-search-tree.py` file with a complete implementation of the binary search tree class. Your first task is to implement the methods `depth_first_for_each` and `breadth_first_for_each` on the `BinarySearchTree` class:
 
-   * `depth_first_for_each(cb)` receives a callback function as a parameter. This method iterates over the binary search tree in [depth-first](https://en.wikipedia.org/wiki/Depth-first_search) order, applying the supplied callback function to each tree element in turn. 
+   * `depth_first_for_each(cb)` receives a callback function as a parameter. This method iterates over the binary search tree in [depth-first](https://en.wikipedia.org/wiki/Depth-first_search) order, applying the supplied callback function to each tree element in turn.
+   *HINT*: In order to achieve depth-first order, you'll probably want to utilize a Stack data structure. 
    * `breadth_first_for_each(cb)` receives a callback function as a parameter. This method iterates over the binary search tree in [breadth-first](https://en.wikipedia.org/wiki/Breadth-first_search) order, applying the supplied callback function to each tree element in turn.
+   *HINT*: In order to achieve breadth-first order, you'll probably want to utilize a Queue data structure.
 
 NOTE: In Python, anonymous functions are referred to as "lambda functions". When passing in a callback function as input to either `depth_first_for_each` or `breadth_first_for_each`, you'll want to define the callbacks as lambda functions. For more information on lambda functions, check out this documentation: [https://docs.python.org/3/tutorial/controlflow.html#lambda-expressions](https://docs.python.org/3/tutorial/controlflow.html#lambda-expressions)
 
-Run `python3 test_binary_search_tree.py` to run the tests for these methods to ensure that your implementation is correct.
+Run `python test_binary_search_tree.py` to run the tests for these methods to ensure that your implementation is correct.
 
 ### Task 2. Implement Heapsort
 Inside the `ex_2` directory you'll find the `heap.py` file with a working implementation of the heap class. Your second task is to implement a sorting method called [heapsort](https://en.wikipedia.org/wiki/Heapsort) that uses the heap data structure in order to sort an array of numbers. Your `heapsort` function should return a new array containing all of the sorted data.
 
-Run `python3 test_heap.py` to run the tests for your `heapsort` function to ensure that your implementation is correct.
+Run `python test_heap.py` to run the tests for your `heapsort` function to ensure that your implementation is correct.
 
 ### Task 3. Analyze some runtimes
 Open up the `Data_Structures_Answers.md` file. This is where you'll jot down your answers for the runtimes of the functions you just implemented. Be sure to also answer any other questions posed in the `Answers.md` file!
 
 ## Algorithms
-For the algorithms portion of the sprint challenge, you'll be answering questions posed in the `exercises.pdf` document inside the `algorithms` directory. Add your answers to the questions in the `Algorithms_Answers.md` file.
+For the algorithms portion of the sprint challenge, you'll be answering questions posed in the `Algorithms_Questions.md` document inside the `algorithms` directory. Add your answers to the questions in the `Algorithms_Answers.md` file.