Searches the specified array of vectors for the specified value using the binary search algorithm. - Java java.lang

Java examples for java.lang:Math Trigonometric Function

  1. HOME
  2. Java
  3. java.lang
  4. Math Trigonometric Function

Description

Searches the specified array of vectors for the specified value using the binary search algorithm.

Demo Code


import java.util.ArrayList;
import java.util.Random;

public class Main{
    /**/*  ww  w  .  j  a  v  a  2s . co m*/
     * Searches the specified array of vectors for the specified value using the
     * binary search algorithm. (this search method has compatibility to Java2
     * (java.util.Arrays)) The array <strong>must</strong> be sorted
     * 
     * @param a
     *            the array to be searched.
     * @param colm
     *            column number in the vector.
     * @param key
     *            the value to be searched for.
     * @return index of the search key, if it is contained in the list;
     *         otherwise, <tt>(-(<i>insertion point</i>) - 1)</tt>. The
     *         <i>insertion point</i> is defined as the point at which the key
     *         would be inserted into the list: the index of the first element
     *         greater than the key, or <tt>list.size()</tt>, if all elements
     *         in the list are less than the specified key. Note that this
     *         guarantees that the return value will be &gt;= 0 if and only if
     *         the key is found.
     */
    public static int binarySearchN(MathVector[] d, double key, int colm) {
        int low, high, middle;
        int num = d.length;

        low = 0;
        high = num - 1;

        try {
            while (low <= high) {
                middle = (low + high) / 2;
                if (key >= d[middle].v(colm) && key < d[middle + 1].v(colm))
                    return middle - 1;
                else if (key < d[middle].v(colm))
                    high = middle - 1;
                else
                    low = middle + 1;
                if (middle >= (num - 1))
                    return num;
                if (middle < 0)
                    return -1;
            }
        } catch (RuntimeException e) {
        }
        return -1;
    }
}

Related Tutorials