problem：
Median of Two Sorted Arrays
什么是median(中值)？
solution中使用的是递归方法，可以自己推导一下下。。。
还没有完全明白，先记录下来。
Seeing someone can't understand why i+j=m−i+n−j (or: m−i+n−j+1)
it's because the lengths of the arrays can be odd or even,
when both are odd or even there is i+j = m−i+n−j
when one array's length is odd and another is even then i+j = m−i+n−j+1
参考
1.leetcode-4-MedianofTwoSortedArrays；
完
