LookupIndex.java
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/******************************************************************************
* Compilation: javac LookupIndex.java
* Execution: java LookupIndex movies.txt "/"
* Dependencies: ST.java Queue.java In.java StdIn.java StdOut.java
* Data files: http://algs4.cs.princeton.edu/35applications/aminoI.csv
* http://algs4.cs.princeton.edu/35applications/movies.txt
*
* % java LookupIndex aminoI.csv ","
* Serine
* TCT
* TCA
* TCG
* AGT
* AGC
* TCG
* Serine
*
* % java LookupIndex movies.txt "/"
* Bacon, Kevin
* Animal House (1978)
* Apollo 13 (1995)
* Beauty Shop (2005)
* Diner (1982)
* Few Good Men, A (1992)
* Flatliners (1990)
* Footloose (1984)
* Friday the 13th (1980)
* ...
* Tin Men (1987)
* DeBoy, David
* Blumenfeld, Alan
* ...
*
******************************************************************************/
package edu.princeton.cs.algs4;
/**
* The {@code LookupIndex} class provides a data-driven client for reading in a
* key-value pairs from a file; then, printing the values corresponding to the
* keys found on standard input. Keys are strings; values are lists of strings.
* The separating delimiter is taken as a command-line argument. This client
* is sometimes known as an <em>inverted index</em>.
* <p>
* For additional documentation, see <a href="http://algs4.cs.princeton.edu/35applications">Section 3.5</a> of
* <i>Algorithms, 4th Edition</i> by Robert Sedgewick and Kevin Wayne.
*
* @author Robert Sedgewick
* @author Kevin Wayne
*/
public class LookupIndex {
// Do not instantiate.
private LookupIndex() { }
public static void main(String[] args) {
String filename = args[0];
String separator = args[1];
In in = new In(filename);
ST<String, Queue<String>> st = new ST<String, Queue<String>>();
ST<String, Queue<String>> ts = new ST<String, Queue<String>>();
while (in.hasNextLine()) {
String line = in.readLine();
String[] fields = line.split(separator);
String key = fields[0];
for (int i = 1; i < fields.length; i++) {
String val = fields[i];
if (!st.contains(key)) st.put(key, new Queue<String>());
if (!ts.contains(val)) ts.put(val, new Queue<String>());
st.get(key).enqueue(val);
ts.get(val).enqueue(key);
}
}
StdOut.println("Done indexing");
// read queries from standard input, one per line
while (!StdIn.isEmpty()) {
String query = StdIn.readLine();
if (st.contains(query))
for (String vals : st.get(query))
StdOut.println(" " + vals);
if (ts.contains(query))
for (String keys : ts.get(query))
StdOut.println(" " + keys);
}
}
}
/******************************************************************************
* Copyright 2002-2016, Robert Sedgewick and Kevin Wayne.
*
* This file is part of algs4.jar, which accompanies the textbook
*
* Algorithms, 4th edition by Robert Sedgewick and Kevin Wayne,
* Addison-Wesley Professional, 2011, ISBN 0-321-57351-X.
* http://algs4.cs.princeton.edu
*
*
* algs4.jar is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* algs4.jar is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with algs4.jar. If not, see http://www.gnu.org/licenses.
******************************************************************************/