zoukankan      html  css  js  c++  java
  • Nested List Weight Sum II

    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.

    Different from the previous question where weight is increasing from root to leaf, now the weight is defined from bottom up. i.e., the leaf level integers have weight 1, and the root level integers have the largest weight.

    Example 1:
    Given the list [[1,1],2,[1,1]], return 8. (four 1's at depth 1, one 2 at depth 2)

    Example 2:
    Given the list [1,[4,[6]]], return 17. (one 1 at depth 3, one 4 at depth 2, and one 6 at depth 1; 1*3 + 4*2 + 6*1 = 17)

    解法一: 和I类似,two pass

    /**
     * // This is the interface that allows for creating nested lists.
     * // You should not implement it, or speculate about its implementation
     * public interface NestedInteger {
     *
     *     // @return true if this NestedInteger holds a single integer, rather than a nested list.
     *     public boolean isInteger();
     *
     *     // @return the single integer that this NestedInteger holds, if it holds a single integer
     *     // Return null if this NestedInteger holds a nested list
     *     public Integer getInteger();
     *
     *     // @return the nested list that this NestedInteger holds, if it holds a nested list
     *     // Return null if this NestedInteger holds a single integer
     *     public List<NestedInteger> getList();
     * }
     */
    public class Solution {
        public int depthSumInverse(List<NestedInteger> nestedList) {
            int sum = 0;
            int level = 0;
            List<NestedInteger> temp = nestedList;
            while(temp.size()!=0)
            {
                List<NestedInteger> list = new ArrayList<NestedInteger>();
                for(int i=0;i<temp.size();i++)
                {
                    if(!temp.get(i).isInteger())
                    {
                         list.addAll(temp.get(i).getList());
                    }
                  
                }
                temp = list;
                level++;
            }
            
            while(nestedList.size()!=0)
            {
                List<NestedInteger> list = new ArrayList<NestedInteger>();
                for(int i=0;i<nestedList.size();i++)
                {
                    if(nestedList.get(i).isInteger())
                    {
                        sum = sum + nestedList.get(i).getInteger()*level;
                    }
                    else
                    {
                        list.addAll(nestedList.get(i).getList());
                    }
                }
                nestedList = list;
                level--;
            }
            return sum; 
        }
    }
  • 相关阅读:
    leecode练习--804、唯一摩尔斯密码词
    leecode练习--832、翻转图像
    leecode练习--561、数组拆分Ⅰ
    leecode练习--942、增减字符串匹配
    第二十篇 编程语言分类
    《英语学习》记录
    《视频笔记》记录
    《爬虫》爬取可用的免费IP
    《读书笔记》记录
    数据结构与算法之美
  • 原文地址:https://www.cnblogs.com/hygeia/p/5731387.html
Copyright © 2011-2022 走看看