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本文介绍了一种求解无限二维网格中按指定顺序访问一系列点所需的最小步数的算法。该算法允许在八个方向上移动，并通过计算相邻点间的水平和垂直距离之和来确定总步数。

You are in an infinite 2D grid where you can move in any of the 8 directions :

 　　(x,y) to 
    (x+1, y), 
    (x - 1, y), 
    (x, y+1), 
    (x, y-1), 
    (x-1, y-1), 
    (x+1,y+1), 
    (x-1,y+1), 
    (x+1,y-1)

You are given a sequence of points and the order in which you need to cover the points. Give the minimum number of steps in which you can achieve it. You start from the first point.

Example :

Input : [(0, 0), (1, 1), (1, 2)]
Output : 2

It takes 1 step to move from (0, 0) to (1, 1). It takes one more step to move from (1, 1) to (1, 2).

This question is intentionally left slightly vague. Clarify the question by trying out a few cases in the “See Expected Output” section.

public class Solution {
    // X and Y co-ordinates of the points in order.
    // Each point is represented by (X.get(i), Y.get(i))
    public int coverPoints(ArrayList<Integer> X, ArrayList<Integer> Y) {
        int x=0;
        int i,j,k;
        for(i=1;i<X.size();++i){
            j=Math.abs(X.get(i)-X.get(i-1));
            k=Math.abs(Y.get(i)-Y.get(i-1));
            x+=(j>k)?j:k;
        }
        return x;

    }
}