Nested List

 1 class Solution {
 2 public:
 3     int depthSum(vector<NestedInteger>& nestedList) {
 4          int res =0;
 5          int level = 1;
 6          for(auto p : nestedList)
 7          {
 8                 res += levelSum(p, level);
 9          }
10          return res;
11     }
12     int levelSum(NestedInteger p, int level)
13     {
14          int res =0;
15          if(p.isInterger()) return level*p.getInterger();
16          for(auto i :p.getList())
17          {
18                  res += levelSum(i, level+1); 
19          }
20          return res;
21     }
22     
23 };

2、Flatten Nested List Iterator

 1 /**
 2  * // This is the interface that allows for creating nested lists.
 3  * // You should not implement it, or speculate about its implementation
 4  * class NestedInteger {
 5  *   public:
 6  *     // Return true if this NestedInteger holds a single integer, rather than a nested list.
 7  *     bool isInteger() const;
 8  *
 9  *     // Return the single integer that this NestedInteger holds, if it holds a single integer
10  *     // The result is undefined if this NestedInteger holds a nested list
11  *     int getInteger() const;
12  *
13  *     // Return the nested list that this NestedInteger holds, if it holds a nested list
14  *     // The result is undefined if this NestedInteger holds a single integer
15  *     const vector<NestedInteger> &getList() const;
16  * };
17  */
18 class NestedIterator {
19 public:
20     void dfs(NestedInteger p)
21     {
22          if(p.isInteger())
23               list.push_back(p.getInteger());
24          for(auto i : p.getList())
25             dfs(i);
26     }
27     NestedIterator(vector<NestedInteger> &nestedList) {
28         for(auto i : nestedList)
29              dfs(i);
30         iter = 0;
31     }
32 
33     int next() {
34         return list[iter++];
35     }
36 
37     bool hasNext() {
38         if(iter<list.size())
39         return true;
40         else return false;
41     }
42 private:
43     vector<int> list;
44     int iter;
45 };
46 
47 /**
48  * Your NestedIterator object will be instantiated and called as such:
49  * NestedIterator i(nestedList);
50  * while (i.hasNext()) cout << i.next();
51  */