// Set this NestedInteger to hold a nested list and adds a nested integer to it.
public void Add(NestedInteger ni)
{
if (_list == null)
{
_list = new List <NestedInteger>();
}
_list.Add(ni);
}
private static int Dfs(NestedInteger ni, int depth)
{
if (ni.IsInteger())
{
return(depth * ni.GetInteger());
}
var sum = 0;
foreach (var n in ni.GetList())
{
sum += Dfs(n, depth + 1);
}
return(sum);
}