HDU2444 二分图

http://acm.hdu.edu.cn/showproblem.php?pid=2444 Problem Description There are a group of students. Some of them may know each other, while others don't. For example, A and B know each other, B and C know each other. But this may not imply that A and C

The Accomodation of Students Time Limit: 5000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 4250    Accepted Submission(s): 1946 Problem Description There are a group of students. Some of them may know each ot

给你一个图,问是否为二分图,若是求出最大匹配. 并查集判图,原理黑白染色. #include <cstdio> #include <cstdlib> #include <cstring> #include <algorithm> #include <cmath> #include <stack> #include <queue> #include <vector> #include <map> #i

There are a group of students. Some of them may know each other, while others don't. For example, A and B know each other, B and C know each other. But this may not imply that A and C know each other. Now you are given all pairs of students who know

传送门:The Accomodation of Students 题意:有n个学生,m对相互认识的,问能否分成两队,使得每对中没有相互认识的,如果可以求最大匹配,否则输出No. 分析:判断二分图用染色法,然后直接匈牙利算法求最大匹配. #include <cstdio> #include <cstring> #include <string> #include <cmath> #include <iostream> #include <al

用染色法判断二分图是这样进行的,随便选择一个点, 1.把它染成黑色,然后将它相邻的点染成白色,然后入队列 2.出队列,与这个点相邻的点染成相反的颜色 根据二分图的特性,相同集合内的点颜色是相同的,即 但是如果这个图不是二分图,那么就会这样 把与1相邻的点2,3染成白色,然后入队列,然后2出队列,要把与2相邻的点2,3染成黑色,但是都染过了,所以不用染色 但是3的颜色应该与2相反(如果是二分图的话),可是没有相反,所以就不是二分图 1 #include <stdio.h> 2 #include

#include<stdio.h> #include<string.h> #include<queue> using namespace std; #define maxn 210 int map[maxn][maxn],color[maxn]; int vis[maxn],match[maxn],n; int bfs(int u,int n) { int i; queue<int>q; q.push(u); color[u]=1; while(!q.emp

//判断是否为二分图:在无向图G中,如果存在奇数回路,则不是二分图.否则是二分图. //判断回路奇偶性:把相邻两点染成黑白两色,如果相邻两点出现颜色相同则存在奇数回路.也就是非二分图. # include <stdio.h> # include <string.h> # include <algorithm> using namespace std; int vis[210],map[210][210],cott[210]; int c[210]; int flag,n

判断一个图是不是二分图 用染色法,二分图是这样一个图: 有两顶点集且图中每条边的的两个顶点分别位于两个顶点集中,每个顶点集中没有边相连接! 判断二分图的常见方法:开始对任意一未染色的顶点染色,之后判断其相邻的顶点中,若未染色则将其染上和相邻顶点不同的颜色, 若已经染色且颜色和相邻顶点的颜色相同则说明不是二分图,若颜色不同则继续判断, 每次用bfs/dfs遍历都可. 二分图最大匹配匈牙利算法: 算法的思路是不停的找增广轨,并增加匹配的个数,增广轨顾名思义是指一条可以使匹配数变多的路径,在匹配问题中