谷歌面试题(一)

大家都知道谷歌是科技界的领头羊，他的面试题肯定有一些参考意义，所以本人就选了几道代表性面试题。给自己或其他人一些帮助
原题:

// Given two 1d vectors, implement an iterator to return their elements alternately.// For example, given two 1d vectors:// v1 = [1, 2]// v2 = [3, 4, 5, 6]// By calling next repeatedly until hasNext returns false, the order of elements returned by next should be: [1, 3, 2, 4, 5, 6].// Follow up: What if you are given k 1d vectors? How well can your code be extended to such cases?/** * Your ZigzagIterator object will be instantiated and called as such:  * ZigzagIterator i = new ZigzagIterator(v1, v2); * while (i.hasNext()) v[f()] = i.next(); */

答案:

public class ZigzagIterator {    private Iterator<Integer> i;    private Iterator<Integer> j;    private Iterator<Integer> temp;    public ZigzagIterator(List<Integer> v1, List<Integer> v2) {        i = v1.iterator();        j = v2.iterator();    }    public int next() {        if(i.hasNext()) {            temp = i;            i = j;            j = temp;        }        return j.next();    }    public boolean hasNext() {        return i.hasNext() || j.hasNext();    }}