二分法查找

import java.util.Arrays;
/**
测试二分法查找
*/
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)/2;

if(value == arr[mid]) {
return mid;
}

if(value > arr[mid]) {
low = mid+1;
}

if(value < arr[mid]) {
high = mid-1;
}
}
return -1; //没有找到
}

}