Given a nested list of integers, return the sum of all integers in the list weighted by their depth.
Each element is either an integer, or a list – whose elements may also be integers or other lists.
Example 1: Given the list [[1,1],2,[1,1]], return 10. (four 1’s at depth 2, one 2 at depth 1)
Example 2: Given the list [1,[4,[6]]], return 27. (one 1 at depth 1, one 4 at depth 2, and one 6 at depth 3; 1 + 4*2 + 6*3 = 27)
求一个nested list权重和.
# """# 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 """ if len(nestedList) == 0: return 0 stack = [] total_weight = 0 for lst in nestedList: stack.append((lst,1)) #add initial weight for lst while(stack): lst, w = stack.pop(0) #get 1st lst and the weight in stack #if is integer, time weight and add to total weight if lst.isInteger(): total_weight += lst.getInteger() * w #if it is not integer, get all the elements in the list and each weight plus 1 else: for child in lst.getList(): stack.append((child,w+1)) return total_weight参考了leetcode的答案
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