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Assignment 6 Binary Search Trees Solution
OBJECTIVES
Build a binary search tree (BST)
Search and traverse a BST
Background
In 2009, Netflix held a competition to see who could best predict user ratings for films based on previous ratings without any other information about the users or films. The grand prize of US$1,000,000 was given to the BellKor's Pragmatic Chaos team which bested Netflix's own algorithm for predicting ratings by 10.06%. This kind of data science is facilitated with the application of good data structures. In fact, cleaning and arranging data in a conducive manner is half the battle in making successful predictions.Imagine you are attempting to predict user ratings given a dataset of IMDB’s top 100 movies. Building a binary search tree will enable you to search for movies and extract their features very efficiently. The movies will be accessed by their titles, but they will also store the following features:
IMDB ranking (1-100)
Title
Year released
IMDB average rating
Your binary search tree will utilize the following struct with default and overloaded constructors:
structMovieNode{
int ranking;
string title;
int year;
float rating;
MovieNode* left = NULL;
MovieNode* right = NULL;
MovieNode(int rank, string t, int y, float r) { title = t;
ranking = rank;
year = y;
rating = r;
}
};
CSCI 2270 – Data Structures
Instructor: Maciej Zagrodzki, Christopher Godley
MovieTree Class
Your code should implement a binary search tree of movies. A header file that lays out this tree can be found in MovieTree.hpp on Moodle. As usual, do not modify the header file. You may implement helper functions in your .cpp file to facilitate recursion if you want as long as you don’t add those functions to the MovieTree class.
MovieTree()
Constructor: Initialize any member variables of the class to default
~MovieTree()
Destructor: Free all memory that was allocated
void printMovieInventory()
Print every node in the tree in alphabetical order of titles using the following format:
// for every Movie node (m) in the tree
cout << "Movie: "<< m-title << " "<< m-rating << endl;
If there is no movie entry in the tree, print the following message instead:
cout << "Tree is Empty. Cannot print"<< endl;
void addMovieNode(int ranking,std::string title,int year,float rating)
Add a node to the tree in the correct place based on its title.Every node’s left children should come before it alphabetically, and every node’s right children should come after it alphabetically. Hint: you can compare strings with <, , ==, string::compare() function etc. You may assume that no two movies have the same title
void findMovie(string title)
Find the movie with the given title,then print out its information:
cout <<"Movie Info:"<<endl;
cout <<"=================="<<endl;
cout <<"Ranking:"<< node-ranking <<endl; cout <<"Title :"<< node-title <<endl; cout <<"Year :"<< node-year <<endl; cout <<"rating :"<< node-rating <<endl;
If the movie isn’t found, print the following message instead:
cout<< "Movie not found."<< endl;
CSCI 2270 – Data Structures
Instructor: Maciej Zagrodzki, Christopher Godley
void queryMovies(float rating,int year)
Print all the movies with a rating at least as good as rating that are newer than yearin the preorderfashionusing the following format:
cout<< "Movies that came out after " << year <<" with rating at least " << rating <<":"<< endl;
each movie that satisfies the constraints should be printed with cout << m-title << "(" << m-year << ") "<< m-rating << endl;
If there is no movie entry in the tree, print the following message instead:
cout << "Tree is Empty. Cannot query Movies"<< endl;
void averageRating()
Print the average rating for all movies in the tree. If the tree is empty, print 0.0. Use the following format:
cout << "Average rating:" << average << endl;
If there is no movie entry in the tree, print the following message instead:
cout << "Average rating:0.0"<< endl;
Driver
Your main function should first read information about each movie from a file and store that information in a MovieTree. The name of the file with this information should be passed in as a command-line argument.An example file is Movies.csvon Moodle. It is in the format:
<Movie 1 ranking,<Movie 1 title,<Movie 1 year,<Movie 1 rating <Movie 2 ranking,<Movie 2 title,<Movie 2 year,<Movie 2 rating Etc…
Note: For autograding’s sake, insert the nodes to the tree in the order they are read in. Of course, they will still be inserted in alphabetical order, but a different insertion order may produce a different tree.After reading the information on each movie from the file, display a menu to the user.
cout<< "======Main Menu======"<< endl; cout<< "1. Find a movie"<< endl;
CSCI 2270 – Data Structures
Instructor: Maciej Zagrodzki, Christopher Godley
cout<< "2. Query movies"<< endl;
cout<< "3. Print the inventory"<< endl; cout<< "4. Average Rating of movies"<< endl; cout<< "5. Quit"<< endl;
The options should have the following behavior:
Find a movie: Call your tree’s findMovie function on a movie specified by the user. Prompt the user for a movie title using the following code:
cout<< "Enter title:"<< endl;
Query movies: Call your tree’s queryMoviesfunction on a rating and year specified by the user. Prompt the user for a rating and year using the following code:
cout<< "Enter minimum rating:"<< endl;
// get user input
cout<< "Enter minimum year:"<< endl;
Print the inventory: Call your tree’s printMovieInventoryfunction
Average Rating of movies: Call your averageRating function
Quit: Exit after printing a friendly message to the user:
