题目描述 In this problem, we would like to talk about unreachable sets of a directed acyclic graph G = (V, E). In mathematics a directed acyclic graph (DAG) is a directed graph with no directed cycles. That is a graph such that there is no way to start a…

题意: 找出不能相互访问的点集的集合的元素数量. 思路: 偏序集最长反链裸题. 代码: #include<iostream> #include<cstring> using namespace std; ; int g[maxn][maxn]; int uN,vN; int linker[maxn]; bool used[maxn]; bool dfs(int u) { ; v < vN; v++) if(g[u][v] && !used[v]) { used…

题目链接 https://nanti.jisuanke.com/t/19979 题意 给出n个点 m 条边 求选出最大的点数使得这个点集之间 任意两点不可达 题目中给的边是有向边 思路 这道题 实际上是求 二分图的最大独立集 二分图的最大独立集 = 顶点数 - 二分图最大匹配 相关概念: https://blog.csdn.net/whosemario/article/details/8513836 那操作就是 先Flyod 跑出 可达矩阵 再二分匹配 答案就是 n - res AC代码 #pr…

题目链接:https://nanti.jisuanke.com/t/19979 题意:给出一个 n 个点,m 条边的 DAG,选出最大的子集使得其中结点两两不能到达. 题解:参考自:https://blog.csdn.net/winter2121/article/details/79849472     首先用弗洛伊德跑出一个可达性矩阵,然后从每个点开始 dfs 跑二分图,则最后 dfs 出的路径为若干条链,而对于链显然除了最后一个结点,其他结点都要删除,而其他结点的总数即跑二分图的匹配数,用总…

题意:给你一张DAG,让你选取最多的点,使得这些点之间互相不可达. 思路:此问题和最小路径可重复点覆盖等价,先在原图上跑一边传递闭包,然后把每个点拆成两个点i, i + n, 原图中的边(a, b)变成(a, b + n),跑一变网络流, 答案就是n - maxflow; 代码: #pragma GCC optimize(3) #pragma GCC optimize("Ofast") #pragma GCC optimize("inline") #pragma G…

node是f2fs重要的管理结构, 它非常重要! 系统挂载完毕后, 会有一个f2fs_nm_info结构的node管理器来管理node的分配. f2fs_nm_info中最让人疑惑的是几颗基数树: struct f2fs_nm_info { block_t nat_blkaddr; /* base disk address of NAT */ nid_t max_nid; /* maximum possible node ids */ nid_t next_scan_nid; /* the ne…

+ASM1@testdb11a /oracle/media/grid$ ./runcluvfy.sh stage -pre crsinst -n testdb11a,testdb11b -verbose Performing pre-checks for cluster services setup Checking node reachability... Check: Node reachability from node "testdb11a" Destination Node…

$ ./runcluvfy.sh stage -pre crsinst -n rac11g1,rac11g2 -verbose Performing pre-checks for cluster services setup Checking node reachability... Check: Node reachability from node "rac11g1" Destination Node Reachable? -----------------------------…

OS: [root@rac ~]# more /etc/oracle-releaseOracle Linux Server release 5.7 DB: SQL> SELECT * FROM V$VERSION; BANNER--------------------------------------------------------------------------------Oracle Database 11g Enterprise Edition Release 11.2.0.3.…

1 环境配置 参考官方文档<Grid Infrastructure Installation Guide for Linux> 1.1 软件环境 操作系统: [root@howe1 ~]# cat /etc/redhat-release Red Hat Enterprise Linux Server release 6.2 (Santiago) [root@howe1 ~]# uname -a Linux howe1 2.6.32-220.el6.i686 #1 SMP Wed Nov 9 0…