0339-nested-list-weight-sum.py

# time complexity: O(n)
# space complexity: O(n)

# class NestedInteger:
#    def __init__(self, value=None):
#        """
#        If value is not specified, initializes an empty list.
#        Otherwise initializes a single integer equal to value.
#        """
#
#    def isInteger(self):
#        """
#        @return True if this NestedInteger holds a single integer, rather than a nested list.
#        :rtype bool
#        """
#
#    def add(self, elem):
#        """
#        Set this NestedInteger to hold a nested list and adds a nested integer elem to it.
#        :rtype void
#        """
#
#    def setInteger(self, value):
#        """
#        Set this NestedInteger to hold a single integer equal to value.
#        :rtype void
#        """
#
#    def getInteger(self):
#        """
#        @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
#        :rtype int
#        """
#
#    def getList(self):
#        """
#        @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
#        :rtype List[NestedInteger]
#        """

from typing import List


class Solution:
    def depthSum(self, nestedList: List[NestedInteger]) -> int:
        def dfs(currList, depth):
            result = 0
            for element in currList:
                if element.isInteger():
                    result += (element.getInteger() * depth)
                else:
                    result += dfs(element.getList(), depth + 1)
            return result
        return dfs(nestedList, 1)