Police Cities Time Limit: 10 Seconds      Memory Limit: 32768 KB Once upon the time there lived a king and he had a big kingdom. And there were n cities in his kingdom and some of them were connected by the roads. And the roads were all one-way becau…

传送门 分析 看到这个题我们的第一反应自然是Tarjan缩点,在这之后我们可以发现实际只要在缩点之后所有出度或入度为0的点布置警察局就可以达到要求,我们用dpij表示考虑前i个出度或入度为0的点共布置了j个警察局,s[i]表示这个点原先由几个点构成,tot表示出度或入度为0的点的总数,所以不难得到转移方程 所以不难得到最终答案 注意此题需要使用高精度. 代码 #include<iostream> #include<cstdio> #include<cstring> #i…

ZOJ 3200 首先我写了个高斯消元,但是消出来了一些奇怪的东西,我就放弃了... 然后只好考虑dp:\(dp[i][j][k]\)表示走到了第i步,到了\((j,k)\)这个节点的概率. 那么答案就是边上节点在所有的步数走到的概率加起来第一次超过\(p%\)的地方. 然后转移的时候枚举现在要走到哪一个方向,走到\((j',k')\),就可以转移到\(dp[i+1][j'][k']\). 然后一共需要走的步数是看对于当前这一步所有的节点所能到达的概率是不是都是0(为了浮点误差,我们需要把=0改…

转自——http://blog.csdn.net/qwe20060514/article/details/8112550 =============================以下是最小生成树+并查集======================================[HDU]1213   How Many Tables   基础并查集★1272   小希的迷宫   基础并查集★1325&&poj1308  Is It A Tree?   基础并查集★1856   More i…

题目链接: http://codeforces.com/problemset/problem/208/C C. Police Station time limit per test:2 secondsmemory limit per test:256 megabytes 问题描述 The Berland road network consists of n cities and of m bidirectional roads. The cities are numbered from 1 to…

两次SPFA 第一关找:从1没有出发点到另一个点的多少是留给油箱 把边反过来再找一遍:重每一个点到终点最少须要多少油 Greedy Driver Time Limit: 2 Seconds      Memory Limit: 65536 KB Edward is a truck driver of a big company. His daily work is driving a truck from one city to another. Recently he got a long d…

主题链接:problemId=203" target="_blank">ZOJ 1203 Swordfish 旗鱼 Swordfish Time Limit: 2 Seconds      Memory Limit: 65536 KB There exists a world within our world A world beneath what we call cyberspace. A world protected by firewalls, password…

POJ 2296 Map Labeler / ZOJ 2493 Map Labeler / HIT 2369 Map Labeler / UVAlive 2973 Map Labeler(2-sat 二分) Description Map generation is a difficult task in cartography. A vital part of such task is automatic labeling of the cities in a map; where for e…

ZOJ Problem Set - 3946 Highway Project Time Limit: 2 Seconds      Memory Limit: 65536 KB Edward, the emperor of the Marjar Empire, wants to build some bidirectional highways so that he can reach other cities from the capital as fast as possible. Thus…

Attack on Titans Time Limit: 2 Seconds      Memory Limit: 65536 KB Over centuries ago, mankind faced a new enemy, the Titans. The difference of power between mankind and their newfound enemy was overwhelming. Soon, mankind was driven to the brink of…