设计一个迭代器来实现摊平二维向量的功能

flatten-2d-vector

样例

例1:

输入:[[1,2],[3],[4,5,6]]
输出:[1,2,3,4,5,6]

例2:

输入:[[7,9],[5]]
输出:[7,9,5]

思路
使用一个 list 存储即可

public class Vector2D implements Iterator<Integer> {
    private List<Integer> list;
    private int count;


    public Vector2D(List<List<Integer>> vec2d) {
        // Initialize your data structure here
        list = new ArrayList<>();
        for (List<Integer> integers : vec2d) {
            for (Integer item : integers) {
                list.add(item);
            }
        }
    }

    @Override
    public Integer next() {
        // Write your code here
        return list.get(count++);

    }

    @Override
    public boolean hasNext() {
        // Write your code here
        return count < list.size();

    }

    @Override
    public void remove() {
    }
}

/**
 * Your Vector2D object will be instantiated and called as such:
 * Vector2D i = new Vector2D(vec2d);
 * while (i.hasNext()) v[f()] = i.next();
 */

源码地址 https://github.com/xingfu0809/Java-LintCode