/**
 * // This is the interface that allows for creating nested lists.
 * // You should not implement it, or speculate about its implementation
 * class NestedInteger {
 *   public:
 *     // Return true if this NestedInteger holds a single integer, rather than a nested list.
 *     bool isInteger() const;
 *
 *     // Return the single integer that this NestedInteger holds, if it holds a single integer
 *     // The result is undefined if this NestedInteger holds a nested list
 *     int getInteger() const;
 *
 *     // Return the nested list that this NestedInteger holds, if it holds a nested list
 *     // The result is undefined if this NestedInteger holds a single integer
 *     const vector<NestedInteger> &getList() const;
 * };
 */

void fillList(list<int> &ls,vector<NestedInteger> &gl)
{
    for(auto i:gl)
    {
        if(i.isInteger())
        {
            ls.push_back(i.getInteger());
            continue;
        }
        fillList(ls,i.getList());
    }
    return;
}

class NestedIterator {
public:
    list<int> ls;
    NestedIterator(vector<NestedInteger> &nestedList) {
        ls.clear();
        for(auto node:nestedList)
        {
            if(node.isInteger())
            {
                ls.push_back(node.getInteger());
            }
            else
            {
                fillList(ls,node.getList());
            }
        }
    }
    
    int next() {
        int ele=ls.front();
        ls.pop_front();
        return ele;
        
    }
    
    bool hasNext() {
        return !ls.empty();
    }
};

/**
 * Your NestedIterator object will be instantiated and called as such:
 * NestedIterator i(nestedList);
 * while (i.hasNext()) cout << i.next();
 */