原题链接在这里:https://leetcode.com/problems/minimum-cost-tree-from-leaf-values/ 题目: Given an array arr of positive integers, consider all binary trees such that: Each node has either 0 or 2 children; The values of arr correspond to the values of each leaf …

思路: 区间dp. 实现: class Solution { public: int mctFromLeafValues(vector<int>& arr) { int n = arr.size(); vector<vector<)); ; i >= ; i--) { for (int j = i; j < n; j++) { if (j == i) maxn[i][j] = arr[i]; else { maxn[i][j] = max(maxn[i][j -…

原题链接在这里:https://leetcode.com/problems/minimum-cost-to-merge-stones/ 题目: There are N piles of stones arranged in a row.  The i-th pile has stones[i] stones. A move consists of merging exactly K consecutive piles into one pile, and the cost of this mov…

原题链接在这里:https://leetcode.com/problems/minimum-cost-for-tickets/ 题目: In a country popular for train travel, you have planned some train travelling one year in advance.  The days of the year that you will travel is given as an array days.  Each day is…

There are N workers.  The i-th worker has a quality[i] and a minimum wage expectation wage[i]. Now we want to hire exactly K workers to form a paid group.  When hiring a group of K workers, we must pay them according to the following rules: Every wor…

There are N workers.  The i-th worker has a quality[i] and a minimum wage expectation wage[i]. Now we want to hire exactly K workers to form a paid group.  When hiring a group of K workers, we must pay them according to the following rules: Every wor…

[LeetCode]Minimum Depth of Binary Tree Given a binary tree, find its minimum depth. The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node. 递归和非递归,此提比较简单.广度优先遍历即可.关键之处就在于如何保持访问深度. 下面是4种代码: im…

There are N piles of stones arranged in a row.  The i-th pile has stones[i] stones. A move consists of merging exactly K consecutive piles into one pile, and the cost of this move is equal to the total number of stones in these K piles. Find the mini…

Leetcode之动态规划(DP)专题-983. 最低票价(Minimum Cost For Tickets) 在一个火车旅行很受欢迎的国度,你提前一年计划了一些火车旅行.在接下来的一年里,你要旅行的日子将以一个名为 days 的数组给出.每一项是一个从 1 到 365 的整数. 火车票有三种不同的销售方式: 一张为期一天的通行证售价为 costs[0] 美元: 一张为期七天的通行证售价为 costs[1] 美元: 一张为期三十天的通行证售价为 costs[2] 美元. 通行证允许数天无限制的旅…

原题链接在这里:https://leetcode.com/problems/connecting-cities-with-minimum-cost/ 题目: There are N cities numbered from 1 to N. You are given connections, where each connections[i] = [city1, city2, cost] represents the cost to connect city1 and city2together…

作者: 负雪明烛 id: fuxuemingzhu 个人博客:http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 Kruskal算法 日期 题目地址:https://leetcode-cn.com/problems/connecting-cities-with-minimum-cost/ 题目描述 There are N cities numbered from 1 to N. You are given connections, where each conne…

We have n chips, where the position of the ith chip is position[i]. We need to move all the chips to the same position. In one step, we can change the position of the ith chip from position[i] to: position[i] + 2 or position[i] - 2 with cost = 0. pos…

作者: 负雪明烛 id: fuxuemingzhu 个人博客:http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 小根堆 日期 题目地址:https://leetcode-cn.com/problems/minimum-cost-to-connect-sticks/ 题目描述 You have some sticks with positive integer lengths. You can connect any two sticks of lengths X…

Given a binary search tree with non-negative values, find the minimum absolute difference between values of any two nodes. Example: Input: 1 \ 3 / 2 Output: 1 Explanation: The minimum absolute difference is 1, which is the difference between 2 and 1…

Given a binary tree, return the values of its boundary in anti-clockwise direction starting from root. Boundary includes left boundary, leaves, and right boundary in order without duplicate nodes. Left boundary is defined as the path from root to the…

一天一道LeetCode 本系列文章已全部上传至我的github,地址:ZeeCoder's Github 欢迎大家关注我的新浪微博,我的新浪微博 欢迎转载,转载请注明出处 (一)题目 来源: https://leetcode.com/problems/binary-tree-level-order-traversal-ii/ Given a binary tree, return the bottom-up level order traversal of its nodes' values.…

给定一个无向图,如果他的某个子图中,任意两个顶点都能互相连通并且是一棵树,那么这棵树就叫做生成树(spanning tree). 如果边上有权值,那么使得边权和最小的生成树叫做最小生成树(MST,Minimum Spanning Tree).       1.prim版本的算法   .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", co…

Problem Link: http://oj.leetcode.com/problems/binary-tree-postorder-traversal/ The post-order-traversal of a binary tree is a classic problem, the recursive way to solve it is really straightforward, the pseudo-code is as follows. RECURSIVE-POST-ORDE…

530. Minimum Absolute Difference in BST Given a binary search tree with non-negative values, find the minimum absolute difference between values of any two nodes. Example: Input:      1     \      3     /    2   Output: 1   Explanation: The minimum a…

一天一道LeetCode 本系列文章已全部上传至我的github,地址:ZeeCoder's Github 欢迎大家关注我的新浪微博,我的新浪微博 欢迎转载,转载请注明出处 (一)题目 来源: https://leetcode.com/problems/binary-tree-zigzag-level-order-traversal/ Given a binary tree, return the zigzag level order traversal of its nodes' values…

There are N piles of stones arranged in a row.  The i-th pile has stones[i] stones. A move consists of merging exactly K consecutive piles into one pile, and the cost of this move is equal to the total number of stones in these K piles. Find the mini…

Given a binary tree, return the values of its boundary in anti-clockwise direction starting from root. Boundary includes left boundary, leaves, and right boundary in order without duplicate nodes.  Left boundary is defined as the path from root to th…

There are N piles of stones arranged in a row.  The i-th pile has stones[i] stones. A move consists of merging exactly K consecutive piles into one pile, and the cost of this move is equal to the total number of stones in these K piles. Find the mini…

Given a binary tree, return the values of its boundary in anti-clockwise direction starting from root. Boundary includes left boundary, leaves, and right boundary in order without duplicate nodes. Left boundary is defined as the path from root to the…

最小生成树——Minimum Spanning Tree,是图论中比较重要的模型,通常用于解决实际生活中的路径代价最小一类的问题.我们首先用通俗的语言解释它的定义: 对于有n个节点的有权无向连通图,寻找n-1条边,恰好将这n个节点相连,并且这n-1条边的权值之和最小. 对于MST问题,通常常见的解法有两种:Prim算法   或者  Kruskal算法+并查集 对于最小生成树,一定要注意其定义是在无向连通图的基础上,如果在有向图中,那么就需要另外的分析,单纯用无向图中的方法是不能得出正确解的,这一…

前言 说到最小生成树(Minimum Spanning Tree),首先要对以下的图论概念有所了解. 图 图(Graph)是表示物件与物件之间的关系的数学对象,是图论的基本研究对象.图的定义方式有两种,其一是二元组定义.图G是一个有序二元组(V,E),其中V称为顶集(Vertices Set),E称为边集(Edges set),E与V不相交.它们亦可写成V(G)和E(G). 边的方向 边是有方向的,单方向(如只允许从点a到达点b)的边称为单向边或有向边:允许双方互达的边称为双向边或无向边.包含单…

On a staircase, the i-th step has some non-negative cost cost[i] assigned (0 indexed). Once you pay the cost, you can either climb one or two steps. You need to find minimum cost to reach the top of the floor, and you can either start from the step w…

leetcode 746. Min Cost Climbing Stairs(easy understanding dp solution) On a staircase, the i-th step has some non-negative cost cost[i] assigned (0 indexed). Once you pay the cost, you can either climb one or two steps. You need to find minimum cost…

[LeetCode]129. Sum Root to Leaf Numbers 解题报告(Python) 标签(空格分隔): LeetCode 题目地址:https://leetcode.com/problems/sum-root-to-leaf-numbers/description/ 题目描述: Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a numbe…

[LeetCode]199. Binary Tree Right Side View 解题报告(Python) 标签: LeetCode 题目地址:https://leetcode.com/problems/binary-tree-right-side-view/description/ 题目描述: Given a binary tree, imagine yourself standing on the right side of it, return the values of the no…