xbb0720的博客

题目链接：点击打开链接题目大意：给定一些标号，与标号之间的大小关系，判断所有给出的关系是否能同时成立。解题思路：其实看到题目就觉得是一个判断是否存在环的问题，但是有点区别就是点与点之间可以有相等的关系，这样的话就貌似不好直接判环：我当时是想非等于关系用单向边连接，而相等关系用双向边连接，然而实际上没什么卵用，等于关系直接成环了...。后面看了标程才知道自己的理解还是很肤浅啊：相等的

H-Highest TowerOni loved to build tall towers of blocks. Her parents were not as amused though. They were on the verge of going crazy over that annoying loud noise when- ever a tower fell to the ground, not to mention having to pick up blocks from the flo

题目链接：点击打开链接（一）题面：DescriptionICPC (Isles of Coral Park City) consist of several beautiful islands.The citizens requested construction of bridges between islands to resolve inconveniences of using boats...

题目链接：UVALive-7818-MicroRNA Ranking（一）题面：Problem description Ahlaam is a computer science student, doing her master thesis on a bioinformatics project about MicroRNAs, special molecule types foun...

题目链接：HDU6311-Cover（一）题面：Problem DescriptionThe Wall has down and the King in the north has to send his soldiers to sentinel.The North can be regard as a undirected graph (not necessary to be co...

（一）题面：题目连接：CodeForces - 238E-Meeting HerUrpal lives in a big city. He has planned to meet his lover tonight.The city has n junctions numbered from 1 to n. The junctions are connected by m direct...

（一）题面：题目链接：CodeForces - 231E - CactusA connected undirected graph is called a vertex cactus, if each vertex of this graph belongs to at most one simple cycle.A simple cycle in a undirected graph...

无向图的割点&&点双联通分量(Tarjan算法)在一个无向图中，对于一个点对（u，v），如果从u至少有两条点不重复路径到达v，那么点u和点v在同一个点双联通分量中。而一个点双联通分量即为包含了尽可能多的这样的（u，v）点对的联通子图，且该分量中的任意两个点（u'，v'）均满足上述条件（除非这个双联通分量仅有这两个点--两个点也是双联通的）。割点定义：在一个联通图中，若删除某个点可以使得该图不再联通，则该点为一个割点（故一个双联通分量中不存在割点）。一个割点可能属于多个不同的双联通分量，除割点外的外只会