364-nested-list-weight-sum-ii.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 unweighted = 0;
        int weighted = 0;
        while (!nestedList.empty()) {
            vector<NestedInteger> nextLevel;
            for (NestedInteger& ni : nestedList) {
                if (ni.isInteger()) {
                    unweighted += ni.getInteger();
                } else {
                    vector<NestedInteger> tmp = ni.getList();
                    for (NestedInteger& n : tmp) {
                        nextLevel.push_back(n);
                    }
                }
            }
            weighted += unweighted;
            nestedList = nextLevel;
        }
        return weighted;
    }
};