Sum of nested list of 'NestedInteger' - Iterative

NestedIntegers1_Iterative.java

public long sum(List<NestedInteger> list) {
  long result = 0;
  Queue<NestedInteger> itemQueue = new LinkedList<NestedInteger>();
  Queue<Integer> depth = new LinkedList<Integer>();
  for(NestedInteger item : list) {
    itemQueue.add(item);
    depth.add(1);
  }
  while(!itemQueue.isEmpty()) {
    NestedInteger item = itemQueue.poll();
    int weight = depth.poll();
    if(item.isInteger()) {
      result += item.getInteger() * weight; 
    }else {
      for(NestedInteger each : item) {
        itemQueue.add(each);
        depth.add(weight + 1);
      }
    }
  }
  return result;
}