![](http://ovteww5gs.bkt.clouddn.com/17-9-21/21

image.png

package xiecheng;

import java.util.Scanner;

public class midNum {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();// 第一个数组的元素个数
        int[] arr1 = new int[n];
        for (int i = 0; i < n; ++i) {
            arr1[i] = sc.nextInt();
        }
        int m = sc.nextInt();// 第二个数组的元素个数
        int[] arr2 = new int[m];
        for (int i = 0; i < m; ++i) {
            arr2[i] = sc.nextInt();
        }
        double res = middleNumberOfTwoArr(arr1, arr2);
        System.out.println(res);
    }

    private static int middleNumberOfTwoArr(int[] arr1, int[] arr2) {

        int start1 = 0;
        int start2 = 0;
        int end1 = arr1.length - 1;
        int end2 = arr2.length - 1;

        int midIndex1;
        int midIndex2;

        while (start1 < end1 || start2 < end2) {
            midIndex1 = (start1 + end1) / 2;
            midIndex2 = (start2 + end2) / 2;
            if (arr1[midIndex1] == arr2[midIndex2]) {
                return arr1[midIndex1];
            }

            if (arr1[midIndex1] < arr2[midIndex2]) {
                if (((end1 - start1) % 2 == 0) && ((end2 - start2) % 2 == 0)) {
                    start1 = midIndex1;
                    end2 = midIndex2;
                } else {
                    start1 = midIndex1 + 1;
                    end2 = midIndex2;
                }
            } else {
                if (((end1 - start1) % 2 == 0) && ((end2 - start2) % 2 == 0)) {
                    start2 = midIndex2;
                    end1 = midIndex1;
                } else {
                    start2 = midIndex2 + 1;
                    end1 = midIndex1;
                }
            }
        }
        if (arr1[start1] < arr2[start2]) {
            return arr1[start1];
        }else if (arr1[start1] > arr2[start2]) {
            return arr2[start2];
        }else {
            return (arr1[start1]+arr2[start2])/2;
        }
    }
}

提交结果;
14%
参考：
http://blog.csdn.net/huberjobs/article/details/51102970