度数分布

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MyComparator.java
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import java.util.*;

/**
$Id: frequencyDistribution.html,v 1.1 2009/06/22 16:12:10 kishi Exp kishi $
@author KISHI Yasuhiro
*/

public class MyComparator implements Comparator {

    public int compare( Object a, Object b ) {
        Integer[] integerA = ( Integer[] ) a;
        Integer[] integerB = ( Integer[] ) b;

        return ( integerA[ 1 ].compareTo( integerB[ 1 ] ) );
    }
}

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RandomTest.java
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import java.util.*;

/**
$Id: frequencyDistribution.html,v 1.1 2009/06/22 16:12:10 kishi Exp kishi $
@author KISHI Yasuhiro
*/

public class RandomTest {

    static public void main( String[] args ) {
        final int NUMBER_OF_OCCURRENCES = 128;
        final int ELEMENT_COUNT = 16;

        Random random = new Random();

        HashMap hm = new HashMap();

        for ( int i = 0;i < NUMBER_OF_OCCURRENCES;i++ ) {
            int result = random.nextInt( ELEMENT_COUNT );

            Integer key = new Integer( result );
            if ( hm.containsKey( key ) ) {
                Integer count = ( Integer ) hm.get( key );

                hm.put( key, new Integer( count.intValue() + 1 ) );

            } else {
                hm.put( key, new Integer( 1 ) );
            }

        }

        /** 発生頻度順で昇順ソートする **/
        /** 同時に度数分布も求める **/
        TreeMap frequencyDistribution = new TreeMap();
        int min = -1;
        int max = -1;
        // Integer型の２次元配列を作成
        Iterator iterator = hm.keySet().iterator();
        Integer[][] array = new Integer[ ELEMENT_COUNT ][];
        for ( int i = 0;i < ELEMENT_COUNT; i++ ) {
            array[ i ] = new Integer[ 2 ];
            if ( iterator.hasNext() ) {
                Integer key = ( Integer ) iterator.next();
                Integer count = ( Integer ) hm.get( key );
                array[ i ][ 0 ] = key;
                array[ i ][ 1 ] = count;

                // 発生頻度の最小値を求める
                if ( min == -1 ) {
                    min = count.intValue();
                } else {
                    if ( min > count.intValue() ) {
                        min = count.intValue();
                    }
                }
                // 発生頻度の最大値を求める
                if ( max == -1 ) {
                    max = count.intValue();
                } else {
                    if ( max < count.intValue() ) {
                        max = count.intValue();
                    }
                }

                //=============================
                // 度数分布を求める
                //=============================
                if ( frequencyDistribution.containsKey( count ) ) {
                    Integer frequency = ( Integer ) frequencyDistribution.get( count );

                    frequencyDistribution.put( count, new Integer( frequency.intValue() + 1 ) );
                } else {
                    frequencyDistribution.put( count, new Integer( 1 ) );
                }
            }
        }

        //========================================================
        // ソート実施
        //========================================================
        MyComparator comparator = new MyComparator();
        Arrays.sort( array, comparator );

        /** 結果の一覧表示 */
        for ( int i = 0;i < array.length;i++ ) {
            for ( int j = 0; j < array[ i ].length;j++ ) {
                System.out.print( "\t" + array[ i ][ j ] );
            }
            System.out.println();
        }

        System.out.println( "最小値: " + min );
        System.out.println( "最大値: " + max );

        //========================================================
        // 度数分布を出力
        //========================================================
        System.out.println( "---------------------------------------------------------------" );
        System.out.println( "【度数分布】" );
        System.out.println( "---------------------------------------------------------------" );
        for ( int i = min;i <= max;i++ ) {
            Integer frequency = ( Integer ) frequencyDistribution.get( new Integer( i ) );

            int occurrence;
            if ( frequency == null ) {
                occurrence = 0;
            } else {
                occurrence = frequency.intValue();
            }

            System.out.print( i + ": " + occurrence + "\t" );
            for ( int j = 0;j < occurrence;j++ ) {
                System.out.print( "*" );
            }
            System.out.println();

        }
    }

}