• Ice_cream's world I HDU


                  ice_cream's world is a rich country, it has many fertile lands. Today, the queen of ice_cream wants award land to diligent ACMers. So there are some watchtowers are set up, and wall between watchtowers be build, in order to partition the ice_cream’s world. But how many ACMers at most can be awarded by the queen is a big problem. One wall-surrounded land must be given to only one ACMer and no walls are crossed, if you can help the queen solve this problem, you will be get a land.InputIn the case, first two integers N, M (N<=1000, M<=10000) is represent the number of watchtower and the number of wall. The watchtower numbered from 0 to N-1. Next following M lines, every line contain two integers A, B mean between A and B has a wall(A and B are distinct). Terminate by end of file.OutputOutput the maximum number of ACMers who will be awarded. 
    One answer one line.Sample Input:

    8 10
    0 1
    1 2
    1 3
    2 4
    3 4
    0 5
    5 6
    6 7
    3 6
    4 7

    Sample Output:

    3
    寻找集合中环的个数!
     1 #include<cstdio>
     2 #include<string>
     3 #include<iostream>
     4 #include<algorithm> 
     5 #define MAX 1005
     6 using namespace std;
     7  
     8 int fa[MAX];
     9 int N,M,cnt;
    10 
    11 int find(int u)
    12 {   if(u!=fa[u]) fa[u]=find(fa[u]);
    13     return fa[u];    
    14 }
    15 
    16 void Union(int a,int b)
    17 {   if(find(a)==find(b)) cnt++;
    18     else fa[find(b)]=find(a);
    19 }
    20 
    21 int main()
    22 {   int k,n,m;
    23     while(cin>>N>>M)
    24     {   for(int i=0;i<=MAX;i++) fa[i]=i;  
    25         for(k=0;k<M;k++)
    26         {   scanf("%d%d",&n,&m);
    27             Union(n,m);
    28         }
    29         cout<<cnt<<endl;
    30         cnt=0;
    31     }
    32 }
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  • 原文地址:https://www.cnblogs.com/zgglj-com/p/6485166.html
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