364. Nested List Weight Sum II ---M ~~~~

Given a nested list of integers, return the sum of all integers in the list weighted by their depth.

Each element is either an integer, or a list -- whose elements may also be integers or other lists.

Different from the previous question where weight is increasing from root to leaf, now the weight is defined from bottom up. i.e., the leaf level integers have weight 1, and the root level integers have the largest weight.

Example 1:

Input: [[1,1],2,[1,1]]
Output: 8 
Explanation: Four 1's at depth 1, one 2 at depth 2.

Example 2:

Input: [1,[4,[6]]]
Output: 17  

Explanation: One 1 at depth 3, one 4 at depth 2, and one 6 at depth 1; 1*3 + 4*2 + 6*1 = 17. 

A:

思路很简单， 就是遇到数字，我们先不计算，因为不知道其最深的depth.

那么我们先计算subList,  并同时找到最大的depth, 然后再对先前存下的数字计算下

/**
 * // This is the interface that allows for creating nested lists.
 * // You should not implement it, or speculate about its implementation
 * class NestedInteger {
 *   public:
 *     // Constructor initializes an empty nested list.
 *     NestedInteger();
 *
 *     // Constructor initializes a single integer.
 *     NestedInteger(int value);
 *
 *     // Return true if this NestedInteger holds a single integer, rather than a nested list.
 *     bool isInteger() const;
 *
 *     // Return the single integer that this NestedInteger holds, if it holds a single integer
 *     // The result is undefined if this NestedInteger holds a nested list
 *     int getInteger() const;
 *
 *     // Set this NestedInteger to hold a single integer.
 *     void setInteger(int value);
 *
 *     // Set this NestedInteger to hold a nested list and adds a nested integer to it.
 *     void add(const NestedInteger &ni);
 *
 *     // Return the nested list that this NestedInteger holds, if it holds a nested list
 *     // The result is undefined if this NestedInteger holds a single integer
 *     const vector<NestedInteger> &getList() const;
 * };
 */
class Solution {
public:
    int depthSumInverse(vector<NestedInteger>& nestedList) {
        int depth =0;
        return helper(nestedList, depth);
    }
private:
    int helper(vector<NestedInteger>& nestedList, int& depth){
        int res = 0;
        vector<int> tmpNum;
        depth = 1;
        for(auto& tmp : nestedList){
            if(tmp.isInteger()){
                tmpNum.push_back(tmp.getInteger());
            }else{
                int tmpDepth =0;
                res += helper(tmp.getList(), tmpDepth);
                depth = max(depth, tmpDepth +1 );
            }
        }
        for(auto v:tmpNum){
            res += v * depth;
        }
        return res;
    }
};

Question:

然而，对于这个例子，我的理解和题目给的不一样

[[-1],[[-1]]]

这里， [-1]  和   【[-1]】，各自都是叶子节点，高度都为1 啊。 

难道是要把[-1]的高度， 算做2？？？？ 没有道理啊

看了别人的答案。

他是先计算出root的高度 为 d ，然后再分别字节点 高度为 d-1