原题是：
Given m arrays, and each array is sorted in ascending order. Now you can pick up two integers from two different arrays (each array picks one) and calculate the distance. We define the distance between two integers a and b to be their absolute difference |a-b|. Your task is to find the maximum distance.
Example 1:
Input:
[[1,2,3],
[4,5],
[1,2,3]]
Output: 4
Explanation:
One way to reach the maximum distance 4 is to pick 1 in the first or third array and pick 5 in the second array.
Note:
Each given array will have at least 1 number. There will be at least two non-empty arrays.
The total number of the integers in all the m arrays will be in the range of [2, 10000].
The integers in the m arrays will be in the range of [-10000, 10000].
思路是：
如何避免最大，最小来自同一个数组，是这个问题的关键。
代码
class Solution:
def maxDistance(self, arrays):
"""
:type arrays: List[List[int]]
:rtype: int
"""
res, curMin, curMax = 0, 10000, -10000
for a in arrays :
res = max(res, max(a[-1]-curMin, curMax-a[0]))
curMin, curMax = min(curMin, a[0]), max(curMax, a[-1])
return res
学到的点
1.
res = max(max, ()）已经是一种常见写法，用于找到最大或者最小值
