/**
 * // 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;
 * };
 */
class Solution {
public:
    // @param nestedList a list of NestedInteger
    // @return a list of integer
    vector<int> re;
    vector<int> flatten(const vector<NestedInteger> &nestedList) {
        // Write your code here
        int sz=nestedList.size();
        for(int i=0;i<sz;i++)
        {
            if(nestedList[i].isInteger())
            {
                re.push_back(nestedList[i].getInteger());
                
            }
            else
            {
                flatten(nestedList[i].getList());
            }
        }
       
        return re;
    }
    
};