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

    https://leetcode.com/problems/nested-list-weight-sum-ii/description/

    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)

    Sol:

    /**
     * // This is the interface that allows for creating nested lists.
     * // You should not implement it, or speculate about its implementation
     * public interface NestedInteger {
     *     // Constructor initializes an empty nested list.
     *     public NestedInteger();
     *
     *     // Constructor initializes a single integer.
     *     public NestedInteger(int value);
     *
     *     // @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();
     *
     *     // Set this NestedInteger to hold a single integer.
     *     public void setInteger(int value);
     *
     *     // Set this NestedInteger to hold a nested list and adds a nested integer to it.
     *     public void add(NestedInteger ni);
     *
     *     // @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) {
            // BFS
            if (nestedList == null) return 0;
            Queue<NestedInteger> queue = new LinkedList<NestedInteger>();
            int prev = 0;
            int total = 0;
            for (NestedInteger next: nestedList){
                queue.offer(next);
            }
            
            while (!queue.isEmpty()){
                int size = queue.size();
                int levelSum = 0;
                for (int i = 0; i < size; i++){
                    NestedInteger current = queue.poll();
                    if (current.isInteger()) levelSum += current.getInteger();
                    List<NestedInteger> nextList = current.getList();
                    if (nextList != null){
                        for (NestedInteger next : nextList){
                            queue.offer(next);
                        }
                    }
                }
                
                prev += levelSum;
                total += prev;
            }
            
            return total;
            
        }
    }
  • 相关阅读:
    HTML5的进步与优势
    jquery项目中一些比较常用的简单方法
    MVC架构下将查询到的数据以表格形式展现出来
    MVC架构下的导出为excel的代码
    MVC中ViewData中数据转化成json形式的变量的方法
    jQuery实现CheckBox全选,全不选,反选代码
    C#导出到EXCEL
    jQuery常见操作实现和常用函数方法总结
    jQuery中运用正则表达式验证输入是否有特殊字符
    DataTime+当前时间转换
  • 原文地址:https://www.cnblogs.com/prmlab/p/7285364.html
Copyright © 2011-2022 走看看