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  • 同构的判断 (全排列+状压)

    Two Graphs

    时间限制:C/C++ 1秒,其他语言2秒
    空间限制:C/C++ 524288K,其他语言1048576K
    64bit IO Format: %lld


    题目描述


    Two undirected simple graphs and where are isomorphic when there exists a bijection on V satisfying if and only if {x, y} ∈ E2. Given two graphs and , count the number of graphs satisfying the following condition: * . * G1 and G are isomorphic.
    输入描述:
    The input consists of several test cases and is terminated by end-of-file.The first line of each test case contains three integers n, m1 and m2 where |E1| = m1 and |E2| = m2.The i-th of the following m1 lines contains 2 integers ai and bi which denote {ai, bi} ∈ E1.The i-th of the last m2 lines contains 2 integers ai and bi which denote {ai, bi} ∈ E2.
    输出描述:
    For each test case, print an integer which denotes the result.

    示例1

    输入
    复制

    3 1 2
    1 3
    1 2
    2 3
    4 2 3
    1 2
    1 3
    4 1
    4 2
    4 3

    输出
    复制

    2
    3

    备注:
    * 1 ≤ n ≤ 8* * 1 ≤ ai, bi ≤ n* The number of test cases does not exceed 50.

    题解:判断同构:判断两个图的邻接矩阵是否一样就行了,枚举G2的所有可能可能情况,用全排列枚举,状压存下来,再放在一个set去重

    代码:

    #include<bits/stdc++.h>
    using namespace std;
    int n,m2,m1;
    #define MAX 10
    #define pii pair<int,int>
    typedef long long ll;
    int G1[MAX][MAX],G2[MAX][MAX];
    map<pii,int>mp;
    set<ll>s;
    int main()
    {
        while(cin>>n>>m1>>m2){
                mp.clear();
                s.clear();
                memset(G1,0,sizeof(G1));
                memset(G2,0,sizeof(G2));
        for(int i=0;i<m1;i++)
        {
            int u,v;
            cin>>u>>v;
            G1[u][v]=G1[v][u]=1;
        }
        for(int i=0;i<m2;i++)
        {
            int u,v;
            cin>>u>>v;
            G2[u][v]=G2[v][u]=1;
             if(u<v)swap(u,v);
            mp[make_pair(u,v)]=i;
        }
        ll ans[MAX];
        for(int i=1;i<=n;i++)
            ans[i]=i;
        do{
            ll state=0;
            bool ok=true;
            for(int i=1;i<=n;i++)
            {
                for(int j=1;j<=n;j++)
                {
                    if(G1[i][j]&&!G2[ans[i]][ans[j]])
                    {
                        ok=false;
                        break;
                    }
                    else
                    {
                        if(G1[i][j])
                        {
                            int u=ans[i];
                            int v=ans[j];
                            if(u<v)swap(u,v);
                            state|=(1LL<<mp[make_pair(u,v)]);
                        }
                    }
                }
                if(!ok)break;
            }
            if(!ok)continue;
            s.insert(state);//cout<<s.size()<<"00000"<<endl;
        }while(next_permutation(ans+1,ans+1+n));
        cout<<s.size()<<endl;
        }
    }
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  • 原文地址:https://www.cnblogs.com/zhgyki/p/9438017.html
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