package leetcode;

import java.util.*;

/**

* // This is the interface that allows for creating nested lists.

* // You should not implement it, or speculate about its implementation

* public interface NestedInteger {

*

* // @return true if this NestedInteger holds a single integer, rather than a nested list.

* public boolean isInteger();

*

* // @return the single integer that this NestedInteger holds, if it holds a single integer

* // Return null if this NestedInteger holds a nested list

* public Integer getInteger();

*

* // @return the nested list that this NestedInteger holds, if it holds a nested list

* // Return null if this NestedInteger holds a single integer

* public List<NestedInteger> getList();

* }

*/

public class NestedIterator implements Iterator<Integer> {

ArrayList<Integer> ret;

Iterator<Integer> it;

public NestedIterator(List<NestedInteger> nestedList) {

ret = new ArrayList<Integer>();

it = ret.iterator();

for(NestedInteger ni:nestedList ){

this.dfs(ni);

}

}

private void dfs(NestedInteger ni){

if(ni.isInteger())

this.ret.add(ni.getInteger());

else {

for(NestedInteger child:ni.getList()){

this.dfs(child);

}

}

}

@Override

public Integer next() {

return it.next();

}

@Override

public boolean hasNext() {

return it.hasNext();

}

@Override

public void remove() {

// TODO Auto-generated method stub

}

public static class MyInteger implements NestedInteger{

private Integer intValue;

private List<NestedInteger> list;

public MyInteger(Integer value) {

this.intValue = value;

}

public MyInteger(List<NestedInteger> l) {

this.list = l;

}

@Override

public boolean isInteger() {

// TODO Auto-generated method stub

return this.list == null;

}

@Override

public Integer getInteger() {

// TODO Auto-generated method stub

return this.intValue;

}

@Override

public List<NestedInteger> getList() {

// TODO Auto-generated method stub

return this.list;

}

}

public static void main(String[] args) {

ArrayList<NestedInteger> arrayList = new ArrayList<NestedInteger>();

Integer i = new Integer(1);

MyInteger m = new MyInteger(i);

arrayList.add(m);

NestedIterator ni = new NestedIterator(arrayList);

while(ni.hasNext())

ni.next();

}

}

/**

* Your NestedIterator object will be instantiated and called as such:

* NestedIterator i = new NestedIterator(nestedList);

* while (i.hasNext()) v[f()] = i.next();

*/