Flatten Nested List Iterator LeetCode solution in C++

1
class NestedIterator {
2
  vector<int> v;
3
  int index;
4
  void helper(vector<NestedInteger> &nestedList, vector<int> &v) {
5
    for (int i = 0; i < nestedList.size(); i++) {
6
      if (nestedList[i].isInteger()) {
7
        v.push_back(nestedList[i].getInteger());
8
      } else {
9
        helper(nestedList[i].getList(), v);
10
      }
11
    }
12
  }
13

14
 public:
15
  NestedIterator(vector<NestedInteger> &nestedList) {
16
    helper(nestedList, v);
17
    index = 0;
18
  }
19

20
  int next() {
21
    return v[index++];
22
  }
23

24
  bool hasNext() {
25
    if (v.size() <= index) {
26
      return false;
27
    }
28
    return true;
29
  }
30
};