JAVA 二分查找

package com.session.chop;

import java.util.Arrays;

/**
 * 二分查找
 */
public class BinarySearch {
public static void main(String[] args) {
int[] array = new int[]{1, 24, 3, 9, 5, 6, 4, 8};
        Arrays.sort(array);
        System.out.println(binarySearch0(array, 0, 8, 4));
    }



private static int binarySearch0(int[] a, int fromIndex, int toIndex,
int key) {
int low = fromIndex;
int high = toIndex - 1;

while (low <= high) {
int mid = (low + high) >>> 1;
int midVal = a[mid];

if (midVal < key)
                low = mid + 1;
else if (midVal > key)
                high = mid - 1;
else
                return mid; // key found
        }
return -(low + 1);  // key not found.
    }
}

转载于:https://www.cnblogs.com/sessionbest/p/8692983.html