Problem
Implement an iterator to flatten a 2d vector.
Example:
Input: 2d vector =
[
[1,2],
[3],
[4,5,6]
]
Output: [1,2,3,4,5,6]
Explanation: By calling next repeatedly until hasNext returns false,
the order of elements returned by next should be: [1,2,3,4,5,6].
Follow up:
As an added challenge, try to code it using only iterators in C++ or iterators in Java.
Solution
public class Vector2D implements Iterator {
private Iterator> rows;
private Iterator row;
public Vector2D(List> vec2d) {
rows = vec2d.iterator();
}
public Integer next() {
if (hasNext()) return row.next();
else return null;
}
//hasNext() is actually moving row iterator to next row
//when it"s null or reached the end of current row
public boolean hasNext() {
while ((row == null || !row.hasNext()) && rows.hasNext()) {
row = rows.next().iterator();
}
return row != null && row.hasNext();
}
}
文章版權(quán)歸作者所有，未經(jīng)允許請(qǐng)勿轉(zhuǎn)載,若此文章存在違規(guī)行為，您可以聯(lián)系管理員刪除。
轉(zhuǎn)載請(qǐng)注明本文地址：http://systransis.cn/yun/71863.html
