二分查找法

二分查找法是用于查找一个数字在一个有序序列中的位置

public class BinarySearch {

    public static int bsearch(int[] array,int findData) {
        int low = 0;
        int high = array.length-1;
        while (low<high) {
            int mid = (low+high)/2;
            if (findData>array[mid]) {
                low = mid+1;
            }else if (findData<array[mid]) {
                high = mid-1;
            }else if (findData == array[mid]) {
                return mid;
            }
        }
        return -1;
    }

    public static void main(String[] args) {
        int[] arr = { 6, 12, 33, 87, 90, 107, 209, 878 };
        System.out.println("87的脚标是:" + (bsearch(arr, 87)));
    }
}

结果:87的脚标是:3