Solution.cpp

/**
 * // 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 maxDepth = 0, ws = 0, s = 0;
        function<void(NestedInteger&, int)> dfs = [&](NestedInteger& x, int d) {
            maxDepth = max(maxDepth, d);
            if (x.isInteger()) {
                ws += x.getInteger() * d;
                s += x.getInteger();
            } else {
                for (auto& y : x.getList()) {
                    dfs(y, d + 1);
                }
            }
        };
        for (auto& x : nestedList) {
            dfs(x, 1);
        }
        return (maxDepth + 1) * s - ws;
    }
};