339. Nested List Weight Sum - cocoder39/coco39_LC GitHub Wiki

339. Nested List Weight Sum

implementation of the class

class NestedInteger:
    def __init__(self, value=None):
        self._is_integer = value is not None
        if self._is_integer:
            self._integer = value
            self._list = None
        else:
            self._integer = None
            self._list = []

    def isInteger(self):
        return self._is_integer

    def getInteger(self):
        return self._integer if self._is_integer else None

    def setInteger(self, value):
        self._is_integer = True
        self._integer = value
        self._list = None

    def add(self, ni):
        if not self._is_integer:
            self._list.append(ni)
        else:
            self._is_integer = False
            self._list = [NestedInteger(self._integer), ni]
            self._integer = None

    def getList(self):
        return self._list if not self._is_integer else None

DFS search

/**
 * // This is the interface that allows for creating nested lists.
 * // You should not implement it, or speculate about its implementation
 * class NestedInteger {
 *   public:
 *     // 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;
 *
 *     // 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 depthSum(vector<NestedInteger>& nestedList) {
        return helper(nestedList, 1);
    }
private:
    int helper(vector<NestedInteger>& nestedList, int depth) {
        int sum = 0;
        for (auto list : nestedList) {
            if (list.isInteger())
                sum += depth * list.getInteger();
            else 
                sum += helper(list.getList(), depth + 1);
        }
        return sum;
    }
};