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/* vim: set expandtab tabstop=4 shiftwidth=4 : */
import java.util.HashMap;
import java.util.Iterator;
public class WordNet
{
// data type space linear in the input size
private HashMap<String, Bag<Integer>> wordsToIds;
private HashMap<Integer, String> idToString;
private Digraph dag;
private SAP sap;
// constructor takes the name of the two input files
// time linearithmic in the input size
public WordNet(String synsets, String hypernyms)
{
int size = 0;
wordsToIds = new HashMap<String, Bag<Integer>>();
idToString = new HashMap<Integer, String>();
// load words from synsets
In syn = new In(synsets);
while (syn.hasNextLine()) {
String line = syn.readLine();
String[] fields = line.split(",");
int id = Integer.parseInt(fields[0]);
String[] words = fields[1].split(" ");
for (String word : words) {
Bag<Integer> bag = wordsToIds.get(word);
if (bag == null) {
bag = new Bag<Integer>();
bag.add(id);
wordsToIds.put(word, bag);
} else {
bag.add(id);
}
}
idToString.put(id, fields[1]);
size++;
}
syn.close();
dag = new Digraph(size);
boolean[] roots = new boolean[dag.V()];
for (int v = 0; v < dag.V(); v++)
roots[v] = true;
// load edges from hypernyms
In hyp = new In(hypernyms);
while (hyp.hasNextLine()) {
String line = hyp.readLine();
String[] fields = line.split(",");
int id = Integer.parseInt(fields[0]);
if (fields.length > 1) roots[id] = false;
for (int i = 1; i < fields.length; i++) {
dag.addEdge(id, Integer.parseInt(fields[i]));
}
}
hyp.close();
int rootsCount = 0;
for (int v = 0; v < dag.V(); v++)
if (roots[v]) rootsCount++;
if (rootsCount != 1)
throw new IllegalArgumentException("roots "+rootsCount);
checkIndegrees();
sap = new SAP(dag);
}
private void checkIndegrees()
{
int[] indegree = new int[dag.V()];
// compute indegrees
for (int v = 0; v < dag.V(); v++) {
for (int w : dag.adj(v)) {
indegree[w]++;
}
}
// initialize queue to contain all vertices with indegree = 0 (leaves)
Queue<Integer> queue = new Queue<Integer>();
for (int v = 0; v < dag.V(); v++)
if (indegree[v] == 0) queue.enqueue(v);
// BFS and decrease indegrees
for (int j = 0; !queue.isEmpty(); j++) {
int v = queue.dequeue();
for (int w : dag.adj(v)) {
indegree[w]--;
if (indegree[w] == 0) queue.enqueue(w);
}
}
// check that all indegrees are 0
for (int v = 0; v < indegree.length; v++) {
if (indegree[v] != 0)
throw new IllegalArgumentException("indegrees");
}
}
// the set of nouns (no duplicates), returned as an Iterable
public Iterable<String> nouns()
{
if (wordsToIds == null) return null;
return wordsToIds.keySet();
}
// is the word a WordNet noun?
public boolean isNoun(String word)
{
if (wordsToIds == null) return false;
return wordsToIds.containsKey(word);
}
// distance between nounA and nounB (defined below)
public int distance(String nounA, String nounB)
{
if (!isNoun(nounA) || !isNoun(nounB))
throw new IllegalArgumentException();
Iterable<Integer> it0 = nounIterable(nounA);
Iterable<Integer> it1 = nounIterable(nounB);
return sap.length(it0, it1);
}
private Iterable<Integer> nounIterable(final String noun) {
return new Iterable<Integer>() {
public Iterator<Integer> iterator() {
return wordsToIds.get(noun).iterator();
}
};
}
// a synset that is the common ancestor of nounA and nounB
// in a shortest ancestral path
public String sap(String nounA, String nounB)
{
if (!isNoun(nounA) || !isNoun(nounB))
throw new java.lang.IllegalArgumentException();
Iterable<Integer> it0 = nounIterable(nounA);
Iterable<Integer> it1 = nounIterable(nounB);
return idToString.get(sap.ancestor(it0, it1));
}
// for unit testing of this class
public static void main(String[] args)
{
WordNet wordNet = new WordNet("./data/synsets.txt", "./data/hypernyms.txt");
StdOut.println("23 white_marlin, mileage: "
+ wordNet.distance("white_marlin", "mileage"));
StdOut.println("32 Black_Plague, black_marlin: "
+ wordNet.distance("Black_Plague", "black_marlin"));
StdOut.println("32 American_water_spaniel, histology: "
+ wordNet.distance("American_water_spaniel", "histology"));
StdOut.println("32 Brown_Swiss, barrel_roll: "
+ wordNet.distance("Brown_Swiss", "barrel_roll"));
StdOut.println("bedspring Carolus_Linnaeus: "
+ wordNet.sap("bedspring", "Carolus_Linnaeus"));
try {
StdOut.println("check roots");
new WordNet("./data/synsets.txt", "./data/hypernymsInvalidTwoRoots.txt");
StdOut.println("BAD");
}
catch (IllegalArgumentException e) { StdOut.println(e.getMessage()); }
try {
StdOut.println("check cycles");
new WordNet("./data/synsets.txt", "./data/hypernymsInvalidCycle.txt");
StdOut.println("BAD");
}
catch (IllegalArgumentException e) { StdOut.println(e.getMessage()); }
}
}
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