Maximum Distance in Arrays

Problem

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:

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.

Solution

public class Solution {
    public int maxDistance(List<List<Integer>> arrays) {
        if (arrays == null || arrays.size() < 2) return 0;
        int min = arrays.get(0).get(0), max = arrays.get(0).get(arrays.get(0).size() - 1);
        int res = Integer.MIN_VALUE;
        for (int i = 1; i < arrays.size(); i++) {
            int curMin = arrays.get(i).get(0), curMax = arrays.get(i).get(arrays.get(i).size() - 1);
            res = Math.max(res, Math.abs(min - curMax));
            res = Math.max(res, Math.abs(max - curMin));
            max = Math.max(max, curMax);
            min = Math.min(min, curMin);
        }
        return res;
    }
}

Analysis

The array inside given arrays is already sorted
Therefore, we know the min and max in each array is the first one and last one
To get the maximum absolute distance between two arrays
We record the max and min so far in each array as curMax and curMin
Then, we compare the distance to our max and min and update the res
After that, we also update max and min at the end of the loop