import edu.princeton.cs.introcs.StdIn; import edu.princeton.cs.introcs.StdOut; /************************************************************************* * Compilation: javac FrequencyCounter.java * Execution: java FrequencyCounter L < input.txt * Dependencies: ST.java StdIn.java StdOut.java * Data files: http://algs4.cs.princeton.edu/31elementary/tnyTale.txt * http://algs4.cs.princeton.edu/31elementary/tale.txt * http://algs4.cs.princeton.edu/31elementary/leipzig100K.txt * http://algs4.cs.princeton.edu/31elementary/leipzig300K.txt * http://algs4.cs.princeton.edu/31elementary/leipzig1M.txt * * Read in a list of words from standard input and print out * the most frequently occurring word that has length greater than * a given threshold. * * % java FrequencyCounter 1 < tinyTale.txt * it 10 * * % java FrequencyCounter 8 < tale.txt * business 122 * * % java FrequencyCounter 10 < leipzig1M.txt * government 24763 * * *************************************************************************/ /** * The FrequencyCounter class provides a client for * reading in a sequence of words and printing a word (exceeding * a given length) that occurs most frequently. It is useful as * a test client for various symbol table implementations. * * For additional documentation, see Section 3.1 of * Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne. * * @author Robert Sedgewick * @author Kevin Wayne */ public class FrequencyCounter { /** * Reads in a command-line integer and sequence of words from * standard input and prints out a word (whose length exceeds * the threshold) that occurs most frequently to standard output. * It also prints out the number of words whose length exceeds * the threshold and the number of distinct such words. */ public static void main(String[] args) { int distinct = 0, words = 0; int minlen = Integer.parseInt(args[0]); ST st = new ST(); // compute frequency counts while (!StdIn.isEmpty()) { String key = StdIn.readString(); if (key.length() < minlen) continue; words++; if (st.contains(key)) { st.put(key, st.get(key) + 1); } else { st.put(key, 1); distinct++; } } // find a key with the highest frequency count String max = ""; st.put(max, 0); for (String word : st.keys()) { if (st.get(word) > st.get(max)) max = word; } StdOut.println(max + " " + st.get(max)); StdOut.println("distinct = " + distinct); StdOut.println("words = " + words); } }