【poj3177】 Redundant Paths】的更多相关文章

http://poj.org/problem?id=3177 (题目链接) 题意 给出一个n个节点m条边的无向图,求最少连几条边使图中没有桥. Solution 我们可以发现,用最少的边使得图中没有桥,那么就是将图缩点得到树,求使每个叶子节点相连所需要的最少边数,即 (叶子节点个数+1)/2 . Tarjan求出图中的桥,以及并查集记录下每个节点属于哪个双连通分量,只与一座桥相连的点即为叶子节点,统计答案即可. 听说会有重边,不过对我的程序好像并没有什么影响. 细节 这道题如果是求双联通分量然后…
1718: [Usaco2006 Jan] Redundant Paths 分离的路径 Time Limit: 5 Sec  Memory Limit: 64 MBSubmit: 964  Solved: 503[Submit][Status][Discuss] Description In order to get from one of the F (1 <= F <= 5,000) grazing fields (which are numbered 1..F) to another f…
求出每个边双连通分量缩点后的度,度为1的点即叶子节点.原图加上(leaf+1)/2条边即可变成双连通图. #include <cstdio> #include <cstring> #include <iostream> #include <algorithm> #include <map> using namespace std; const int N = 5010; const int M = 10010; struct Edge { int…
http://poj.org/problem?id=3177 又写了一遍手动栈... 把边双都缩点,缩成一棵树,答案就是树中度数为1的点的个数除2上取整. 为什么呢?因为1个度数为1的点的树需要多连0条边,2个度数为1的点的树需要多连1条边,3个度数为1的点的树需要多连2条边. 然后对于n(n>3)个度数为1的点的树,连一次边后再缩点能变成有n-2个度数为1的点的树. 无向图边双跟有向图强连通分量的求法很像喔,重点在于特判后继节点是否是自己的father连过来的边. #include<cstd…
A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below). The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner of the grid (marked 'Finish' in t…
Unique Paths II Total Accepted: 22828 Total Submissions: 81414My Submissions Follow up for "Unique Paths": Now consider if some obstacles are added to the grids. How many unique paths would there be? An obstacle and empty space is marked as 1 an…
A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below). The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner of the grid (marked 'Finish' in t…
A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below). The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner of the grid (marked 'Finish' in t…
题目: Follow up for "Unique Paths": Now consider if some obstacles are added to the grids. How many unique paths would there be? An obstacle and empty space is marked as 1 and 0 respectively in the grid. For example, There is one obstacle in the m…
题目: A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below). The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner of the grid (marked 'Finish'…