339. Nested List Weight Sum

DepthSum.cs

public class Solution {
  public int DepthSum(IList<NestedInteger> nestedList) {
    int Traverse(in IList<NestedInteger> list, in int depth =  1){
      var sum = 0;
      foreach(var e in list){
        if(e.IsInteger()){
          sum += e.GetInteger() * depth;
          continue;
        }
        sum += Traverse(e.GetList(), depth + 1);
      }
      return sum;
    }

    return Traverse(nestedList);
  }
}