二分查找

import java.util.Arrays;
 
/**
 * 测试二分法查找
 * 二分法适用于已经排好序的数组
 * @author Administrator
 *
 */
public class TestBinarySearch {
	public static void main(String[] args) {
		int[] arr= {30,20,50,10,80,9,7,12,100,40,8};
		Arrays.sort(arr);
		System.out.println(Arrays.toString(arr));
		System.out.println(myBinarySearch(arr,40));
		}
	
	public static int myBinarySearch(int[] arr,int value) {
		int low=0;
		int high=arr.length-1;
		while(low<=high) {
			int mid=low + (high-low)/2;
			if(value==arr[mid]) {
				return mid;
				}
			if(value>arr[mid]) {
				low=mid+1;	
			}
			if(value