binary Search int array - Java Collection Framework

Java examples for Collection Framework:Array Search

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Description

binary Search int array

Demo Code

/*//  ww  w .  j  a  va 2  s . c o  m
 * Copyright (c) 2013 Menny Even-Danan
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import java.lang.reflect.Method;
import java.util.Arrays;

public class Main{
    public static void main(String[] argv) throws Exception{
        int[] array = new int[]{34,35,36,37,37,37,67,68,69};
        int startIndex = 2;
        int endIndex = 2;
        int value = 2;
        System.out.println(binarySearch(array,startIndex,endIndex,value));
    }
    private static final Method METHOD_Arrays_binarySearch = CompatUtils
            .getMethod(Arrays.class, "binarySearch", int[].class,
                    int.class, int.class, int.class);
    public static int binarySearch(int[] array, int startIndex,
            int endIndex, int value) {
        if (METHOD_Arrays_binarySearch != null) {
            final Object index = CompatUtils.invoke(null, 0,
                    METHOD_Arrays_binarySearch, array, startIndex,
                    endIndex, value);
            return (Integer) index;
        } else {
            return compatBinarySearch(array, startIndex, endIndex, value);
        }
    }
    static int compatBinarySearch(int[] array, int startIndex,
            int endIndex, int value) {
        if (startIndex > endIndex)
            throw new IllegalArgumentException();
        if (startIndex < 0 || endIndex > array.length)
            throw new ArrayIndexOutOfBoundsException();

        final int work[] = new int[endIndex - startIndex];
        System.arraycopy(array, startIndex, work, 0, work.length);
        final int index = Arrays.binarySearch(work, value);
        if (index >= 0) {
            return index + startIndex;
        } else {
            return ~(~index + startIndex);
        }
    }
}

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