P3352 Road Construction 描述 这几乎是夏季,这意味着它几乎是夏季施工时间!今年,负责岛屿热带岛屿天堂道路的优秀人士,希望修复和升级岛上各个旅游景点之间的各种道路. 道路本身也很有趣.由于岛上奇特的风俗习惯,道路的布置使得它们不会在十字路口相遇,而是通过桥梁和隧道在彼此之间穿过或穿过.这样,每条道路都在两个特定的旅游景点之间运行,这样游客不会失去不可挽回的收入. 不幸的是,鉴于每条道路上所需的维修和升级的性质,当建筑公司在特定的道路上工作时,它在任何方向都不可用.如果不能在…

 http://blog.csdn.net/geniusluzh/article/details/6619575 在说Tarjan算法解决桥和边双连通分量问题之前我们先来回顾一下Tarjan算法是如何求解强连通分量的. Tarjan算法在求解强连通分量的时候,通过引入dfs过程中对一个点访问的顺序dfsNum(也就是在访问该点之前已经访问的点的个数)和一个点可以到达的最小的dfsNum的low数组,当我们遇到一个顶点的dfsNum值等于low值,那么该点就是一个强连通分量的根.因为我们在dfs的…

POJ 3177 Redundant Paths POJ 3352 Road Construction 题目链接 题意:两题一样的.一份代码能交.给定一个连通无向图,问加几条边能使得图变成一个双连通图 思路:先求双连通.缩点后.计算入度为1的个数,然后(个数 + 1) / 2 就是答案(这题因为是仅仅有一个连通块所以能够这么搞,假设有多个,就不能这样搞了) 代码: #include <cstdio> #include <cstring> #include <algorithm…

题目大意:给定一个4位素数,一个目标4位素数.每次变换一位,保证变换后依然是素数,求变换到目标素数的最小步数. 解题报告:直接用最短路. 枚举1000-10000所有素数,如果素数A交换一位可以得到素数B,则在AB间加入一条长度为1的双向边. 则题中所求的便是从起点到终点的最短路.使用Dijkstra或SPFA皆可. 当然,纯粹的BFS也是可以的. 用Dijkstra算法A了题目之后,看了一下Discuss,发现了一个新名词,双向BFS. 即从起点和终点同时进行BFS,相遇则求得最短路. 借鉴了…

Road Construction Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 10141   Accepted: 5031 Description It's almost summer time, and that means that it's almost summer construction time! This year, the good people who are in charge of the r…

题目地址: http://poj.org/problem?id=2376 题目内容: Cleaning Shifts Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 12226   Accepted: 3187 Description Farmer John is assigning some of his N (1 <= N <= 25,000) cows to do some cleaning chores arou…

题目地址: http://poj.org/problem?id=1611 题目内容: The Suspects Time Limit: 1000MS   Memory Limit: 20000K Total Submissions: 24253   Accepted: 11868 Description Severe acute respiratory syndrome (SARS), an atypical pneumonia of unknown aetiology, was recogni…

题目地址: http://poj.org/problem?id=2524 题目内容: Ubiquitous Religions Time Limit: 5000MS   Memory Limit: 65536K Total Submissions: 26119   Accepted: 12859 Description There are so many different religions in the world today that it is difficult to keep tra…

Description In order to get from one of the F (1 <= F <= 5,000) grazing fields (which are numbered 1..F) to another field, Bessie and the rest of the herd are forced to cross near the Tree of Rotten Apples. The cows are now tired of often being forc…

    487-3279 Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 228365   Accepted: 39826 Description Businesses like to have memorable telephone numbers. One way to make a telephone number memorable is to have it spell a memorable word or p…