Nested List Weight Sum

Problem: Nested List Weight Sum

Do depth-first search on every element. If we get integer multiply it with depth and add to sum. If we get list, continue to do depth-first search with further depth until we get integers.

Code in Python:

# """
# This is the interface that allows for creating nested lists.
# You should not implement it, or speculate about its implementation
# """
#class NestedInteger(object):
#    def isInteger(self):
#        """
#        @return True if this NestedInteger holds a single integer, rather than a nested list.
#        :rtype bool
#        """
#
#    def getInteger(self):
#        """
#        @return the single integer that this NestedInteger holds, if it holds a single integer
#        Return None 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
#        Return None if this NestedInteger holds a single integer
#        :rtype List[NestedInteger]
#        """

class Solution(object):
    def depthSum(self, nestedList):
        """
        :type nestedList: List[NestedInteger]
        :rtype: int
        """
        def dfs(nestedList, depth):
            return sum(depth*element.getInteger() if element.isInteger() else dfs(element.getList(), depth+1) for element in nestedList)

        return dfs(nestedList, 1)