• Codeforces Round #286 (Div. 2) B. Mr. Kitayuta's Colorful Graph dfs


    B. Mr. Kitayuta's Colorful Graph
    time limit per test
    1 second
    memory limit per test
    256 megabytes
    input
    standard input
    output
    standard output

    Mr. Kitayuta has just bought an undirected graph consisting of n vertices and m edges. The vertices of the graph are numbered from 1 to n. Each edge, namely edge i, has a color ci, connecting vertex ai and bi.

    Mr. Kitayuta wants you to process the following q queries.

    In the i-th query, he gives you two integers — ui and vi.

    Find the number of the colors that satisfy the following condition: the edges of that color connect vertex ui and vertex vi directly or indirectly.

    Input

    The first line of the input contains space-separated two integers — n and m (2 ≤ n ≤ 100, 1 ≤ m ≤ 100), denoting the number of the vertices and the number of the edges, respectively.

    The next m lines contain space-separated three integers — aibi (1 ≤ ai < bi ≤ n) and ci (1 ≤ ci ≤ m). Note that there can be multiple edges between two vertices. However, there are no multiple edges of the same color between two vertices, that is, if i ≠ j,(ai, bi, ci) ≠ (aj, bj, cj).

    The next line contains a integer — q (1 ≤ q ≤ 100), denoting the number of the queries.

    Then follows q lines, containing space-separated two integers — ui and vi (1 ≤ ui, vi ≤ n). It is guaranteed that ui ≠ vi.

    Output

    For each query, print the answer in a separate line.

    Examples
    input
    4 5
    1 2 1
    1 2 2
    2 3 1
    2 3 3
    2 4 3
    3
    1 2
    3 4
    1 4
    output
    2
    1
    0
    input
    5 7
    1 5 1
    2 5 1
    3 5 1
    4 5 1
    1 2 2
    2 3 2
    3 4 2
    5
    1 5
    5 1
    2 5
    1 5
    1 4
    output
    1
    1
    1
    1
    2
    Note

    Let's consider the first sample.

    The figure above shows the first sample.
    • Vertex 1 and vertex 2 are connected by color 1 and 2.
    • Vertex 3 and vertex 4 are connected by color 3.
    • Vertex 1 and vertex 4 are not connected by any single color.

      题意:给你一个图n个点,m条边;

         每条边有个颜色,每次u,v只能走一条颜色的路径;

         求有多少条路;

      思路:暴力dfs;

    #include<bits/stdc++.h>
    using namespace std;
    #define ll long long
    #define pi (4*atan(1.0))
    #define eps 1e-14http://v.ifeng.com/program/lyyy/
    const int N=2e5+10,M=1e6+10,inf=1e9+10,MOD=2009;
    const ll INF=1e18+10;
    struct edge
    {
        int v,w;
        int nex;
    }edge[N];
    int head[N],edg;
    void init()
    {
        memset(head,-1,sizeof(head));
        edg=0;
    }
    void add(int u,int v,int w)
    {
        ++edg;
        edge[edg].v=v;
        edge[edg].w=w;
        edge[edg].nex=head[u];
        head[u]=edg;
    }
    int now,to,ans;
    int flag[N];
    int hh[N];
    void dfs(int u,int pre)
    {
        //cout<<u<<" "<<pre<<endl;
        if(u==to)
        {
            if(!hh[pre]&&pre!=-1)
            {
                ans++;
    
                hh[pre]=1;
            }
            return;
        }
        for(int i=head[u];i!=-1;i=edge[i].nex)
        {
            int v=edge[i].v;
            if(flag[v])continue;
            int w=edge[i].w;
            if(pre==-1||w==pre)
            {
                flag[v]=1;
                dfs(v,w);
                flag[v]=0;
            }
        }
    }
    int main()
    {
        init();
        int n,m;
        scanf("%d%d",&n,&m);
        for(int i=0;i<m;i++)
        {
            int u,v,w;
            scanf("%d%d%d",&u,&v,&w);
            add(u,v,w);
            add(v,u,w);
        }
        int q;
        scanf("%d",&q);
        while(q--)
        {
            memset(hh,0,sizeof(hh));
            ans=0;
            scanf("%d%d",&now,&to);
            flag[now]=1;
            dfs(now,-1);
            flag[now]=0;
            printf("%d
    ",ans);
        }
        return 0;
    }
  • 相关阅读:
    less 28-31
    less27 27a
    sqli 26 26a
    sqli lab 25 25a
    kail 更新源
    sqli lab 23 、24
    less 20 21 22
    less18 19
    less 17
    数字类型,字符串类型,列表类型
  • 原文地址:https://www.cnblogs.com/jhz033/p/6031555.html
Copyright © 2020-2023  润新知