Given an directed graph, a topological order of the graph nodes is defined as follow: For each directed edge A-->B in graph, A must before B in the order list. The first node in the order can be any node in the graph with no nodes direct to it. Find…

DZY Loves Topological Sorting Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others) Total Submission(s): 866    Accepted Submission(s): 250 Problem Description A topological sort or topological ordering of a directed g…

Topological Sorting Time limit: 1.0 secondMemory limit: 64 MB Michael wants to win the world championship in programming and decided to study N subjects (for convenience we will number these subjects from 1 to N). Michael has worked out a study plan…

Topological sorting/ ordering is a linear ordering of its vertices such that for every directed edge uv from vertex u to vertex v, u comes before v in the ordering. We can conduct topological sorting only on DAG (directed acyclic graph). Therefore, t…

Find Function Optimization: After Path compression: int find(int x){ return root[x] == x ? x : (root[x] = find(root[x])); } Avoid Stack overflow: int find(int a){ while(root[a]!=a){ a=root[a]; } return a; }  Combined with rank : (Combined with the he…

一.什么是拓扑排序 在图论中,拓扑排序(Topological Sorting)是一个有向无环图(DAG, Directed Acyclic Graph)的所有顶点的线性序列.且该序列必须满足下面两个条件: 每个顶点出现且只出现一次. 若存在一条从顶点 A 到顶点 B 的路径,那么在序列中顶点 A 出现在顶点 B 的前面. 有向无环图(DAG)才有拓扑排序,非DAG图没有拓扑排序一说. 例如,下面这个图: 它是一个 DAG 图,那么如何写出它的拓扑排序呢?这里说一种比较常用的方法: 从 DAG…

定义: Topological Sorting is a method of arranging the vertices in a directed acyclic graph (DAG有向无环图) as a sequence, such that for every directed edge(u,v), 即u-> v, vertex u comes before v in the ordering 注意: A topological ordering is possible if and…

［抄题］: 现在你总共有 n 门课需要选,记为 0 到 n - 1.一些课程在修之前需要先修另外的一些课程,比如要学习课程 0 你需要先学习课程 1 ,表示为[0,1]给定n门课以及他们的先决条件,判断是否可能完成所有课程? 给定 n = 2,先决条件为 [[1,0]] 返回 true给定 n = 2,先决条件为 [[1,0],[0,1]] 返回 false ［思维问题］: 不知道为啥是图:抽象图,很多条边构造出来的图 ［一句话思路］: 拓扑排序:先统计度.边数,再把度=0的点放进queue,进…

DZY Loves Topological Sorting Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)Total Submission(s): 1250    Accepted Submission(s): 403 Problem Description A topological sort or topological ordering of a directed g…

DZY Loves Topological Sorting Time Limit: 1 Sec  Memory Limit: 256 MB 题目连接 http://acm.hdu.edu.cn/showproblem.php?pid=5195 Description A topological sort or topological ordering of a directed graph is a linear ordering of its vertices such that for ev…

传送门 DZY Loves Topological Sorting Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)Total Submission(s): 221    Accepted Submission(s): 52 Problem Description A topological sort or topological ordering of a directed…

拓扑排序(Topological Sorting) 一.拓扑排序 含义 构造AOV网络全部顶点的拓扑有序序列的运算称为拓扑排序(Topological Sorting). 在图论中,拓扑排序(Topological Sorting)是一个有向无环图(DAG, Directed Acyclic Graph)的所有顶点的线性序列. 且该序列必须满足下面两个条件: ①每个顶点出现且只出现一次. ②若存在一条从顶点 A 到顶点 B 的路径,那么在序列中顶点 A 出现在顶点 B 的前面. 注:有向无环图(…

题意: 删去K条边,使拓扑排序后序列字典序最大 分析: 因为我们要求最后的拓扑序列字典序最大,所以一定要贪心地将标号越大的点越早入队.我们定义点i的入度为di. 假设当前还能删去k条边,那么我们一定会把当前还没入队的di≤k的最大的i找出来,把它的di条入边都删掉,然后加入拓扑序列. 删除的一定是小连大的边,因为大连小的边在拓扑序列生成的时候就去掉了 #include <iostream> #include <cstdio> #include <queue> #incl…

传送门 题意简述:给出一张DAGDAGDAG,要求删去不超过kkk条边问最后拓扑序的最大字典序是多少. 思路:贪心帮当前不超过删边上限且权值最大的点删边,用线段树维护一下每个点的入度来支持查询即可. 注意要在选点的时候更新后继的入度 代码: #include<bits/stdc++.h> #define ri register int using namespace std; inline int read(){ int ans=0; char ch=getchar(); while(!isd…

题目链接: hdu:http://acm.hdu.edu.cn/showproblem.php?pid=5195 bc(中文):http://bestcoder.hdu.edu.cn/contests/contest_chineseproblem.php?cid=573&pid=1002 题解: 1.拓扑排序+贪心 #include<algorithm> #include<iostream> #include<cstring> #include<cstdi…

Yet Another Source Code for LintCode Current Status : 232AC / 289ALL in Language C++, Up to date (2016-02-10) For more problems and solutions, you can see my LintCode repository. I'll keep updating for full summary and better solutions. See cnblogs t…

刷题备忘录,for bug-free leetcode 396. Rotate Function 题意: Given an array of integers A and let n to be its length. Assume Bk to be an array obtained by rotating the array A k positions clock-wise, we define a "rotation function" F on A as follow: F(k…

http://www.lintcode.com/zh-cn/problem/topological-sorting/# 给定一个有向图,图节点的拓扑排序被定义为: 对于每条有向边A--> B,则A必须排在B之前 拓扑排序的第一个节点可以是任何在图中没有其他节点指向它的节点 找到给定图的任一拓扑排序 solution Topological Sorting Topological sorting for Directed Acyclic Graph (DAG) is a linear orderi…

刷题备忘录,for bug-free 招行面试题--求无序数组最长连续序列的长度,这里连续指的是值连续--间隔为1,并不是数值的位置连续 问题: 给出一个未排序的整数数组,找出最长的连续元素序列的长度. 如: 给出[100, 4, 200, 1, 3, 2], 最长的连续元素序列是[1, 2, 3, 4].返回它的长度:4. 你的算法必须有O(n)的时间复杂度 . 解法: 初始思路 要找连续的元素,第一反应一般是先把数组排序.但悲剧的是题目中明确要求了O(n)的时间复杂度,要做一次排序,是不能达…

最近开始刷lintcode,记录下自己的答案,数字即为lintcode题目号,语言为python3,坚持日拱一卒吧... (一). 回文字符窜问题(Palindrome problem) 627. Longest Palindrome 给出一个包含大小写字母的字符串.求出由这些字母构成的最长的回文串的长度是多少. 数据是大小写敏感的,也就是说,"Aa" 并不会被认为是一个回文串 输入 : s = "abccccdd" 输出 : 7 说明 : 一种可以构建出来的最长回…

There is a new alien language which uses the latin alphabet. However, the order among letters are unknown to you. You receive a list of words from the dictionary, where words are sorted lexicographically by the rules of this new language. Derive the…

能够用 BFS 解决的问题,一定不要用 DFS 去做! 因为用 Recursion 实现的 DFS 可能造成 StackOverflow! (NonRecursion 的 DFS 一来你不会写,二来面试官也看不懂) 1. Queue Python中,使用collections.deque,双端队列 class MyQueue: # 队列初始化 def __init__(self): self.elements = [] # 用list存储队列元素 self.pointer = 0 # 队头位置…

BFS模板,记住这5个: (1)针对树的BFS 1.1 无需分层遍历 from collections import deque def levelOrderTree(root): if not root: return q = deque([root]) while q: head = q.popleft() do something with this head node... if head.left: q.append(head.left) if head.right: q.append…

1图论: 1.1  133. Clone Graph https://leetcode.com/problems/clone-graph/#/description 思路:这题可以对照拷贝随机链表那道题,首先拷贝图中的节点,然后拷贝每个结点的neighbors数组. 这题使用BFS,所有的BFS都可以看成是queue和unordered_map的组合实现的,该题模拟实现了一个queue,主要是因为后面要判断某个元素是否已经访问,所以使用一个vector来模拟操作,传统的queue会弹出元素,还需…

Java基础常见英语词汇(共70个) ['ɔbdʒekt] ['ɔ:rientid]导向的                             ['prəʊɡræmɪŋ]编程 OO: object-oriented ,面向对象 OOP: object-oriented programming,面向对象编程 [dɪ'veləpmənt][kɪt]工具箱                              ['vɜːtjʊəl]虚拟的 JDK:Java development kit, j…

I am Nexus Master!  The 13th Zhejiang University Programming Contest 参见:http://www.bnuoj.com/bnuoj/problem_show.php?pid=29137 题意就理解错了!!! 之后乱搞就也错了!!! Current Server Time: 2013-08-30 23:29:55 I am Nexus Master! Time Limit: 2000ms Memory Limit: 65536KB…

写在前面的话:关于数据结构与算法讲解的书籍很多,但是用python语言去实现的不是很多,最近有幸看到一本这样的书籍,由Brad Miller and David Ranum编写的<Problem Solving with Algorithms and Data Structures Using Python>,地址为:http://interactivepython.org/runestone/static/pythonds/index.html是英文的,写的不错,里面代码的实现也很详细,很多…

找规律水题... Traveling Cellsperson Time Limit: 1000ms Memory Limit: 65535KB This problem will be judged on UESTC. Original ID: 185264-bit integer IO format: %lld      Java class name: Main Prev Submit Status Statistics Discuss Next Font Size: + - Type:  …

状压DP... Kings on a Chessboard Time Limit: 10000ms Memory Limit: 65535KB This problem will be judged on UESTC. Original ID: 185164-bit integer IO format: %lld      Java class name: Main Prev Submit Status Statistics Discuss Next Font Size: + - Type:  …

Query on a tree Time Limit: 5000ms Memory Limit: 262144KB   This problem will be judged on SPOJ. Original ID: QTREE64-bit integer IO format: %lld      Java class name: Main Prev Submit Status Statistics Discuss Next Font Size: + - Type:   None Graph…