zoukankan      html  css  js  c++  java
  • POJ 2449 Remmarguts' Date k短路

    Remmarguts' Date
    Time Limit: 4000MS   Memory Limit: 65536K
    Total Submissions: 17094   Accepted: 4694

    Description

    "Good man never makes girls wait or breaks an appointment!" said the mandarin duck father. Softly touching his little ducks' head, he told them a story. 

    "Prince Remmarguts lives in his kingdom UDF – United Delta of Freedom. One day their neighboring country sent them Princess Uyuw on a diplomatic mission." 

    "Erenow, the princess sent Remmarguts a letter, informing him that she would come to the hall and hold commercial talks with UDF if and only if the prince go and meet her via the K-th shortest path. (in fact, Uyuw does not want to come at all)" 

    Being interested in the trade development and such a lovely girl, Prince Remmarguts really became enamored. He needs you - the prime minister's help! 

    DETAILS: UDF's capital consists of N stations. The hall is numbered S, while the station numbered T denotes prince' current place. M muddy directed sideways connect some of the stations. Remmarguts' path to welcome the princess might include the same station twice or more than twice, even it is the station with number S or T. Different paths with same length will be considered disparate. 

    Input

    The first line contains two integer numbers N and M (1 <= N <= 1000, 0 <= M <= 100000). Stations are numbered from 1 to N. Each of the following M lines contains three integer numbers A, B and T (1 <= A, B <= N, 1 <= T <= 100). It shows that there is a directed sideway from A-th station to B-th station with time T. 

    The last line consists of three integer numbers S, T and K (1 <= S, T <= N, 1 <= K <= 1000).

    Output

    A single line consisting of a single integer number: the length (time required) to welcome Princess Uyuw using the K-th shortest path. If K-th shortest path does not exist, you should output "-1" (without quotes) instead.

    Sample Input

    2 2
    1 2 5
    2 1 4
    1 2 2
    

    Sample Output

    14







    #include <iostream>
    #include <cstdio>
    #include <queue>
    #include <cstring>
    
    using namespace std;
    
    const int maxn=1111;
    const int maxm=111111;
    const int INF=1e9;
    
    struct ANODE
    {
        int id;
        int f;
        int g;
        bool operator < (const ANODE &t) const
        {
            if (t.f==f) return t.g<g;
            return t.f<f;
        }
    };
    
    struct EDGE
    {
        int to;
        int w;
        int next;
    }edges[maxm],unti_edges[maxm];
    
    int node,src,dest,edge;
    int head[maxn],dist[maxn];
    
    int unti_head[maxn],unti_edge;
    
    void prepare(int _node,int _src=0,int _dest=0)
    {
        node=_node,src=_src,dest=_dest;
        for (int i=0; i<=node; i++) head[i]=-1;
        edge=0;
        for (int i=0; i<=node; i++) unti_head[i]=-1;
        unti_edge=0;
    }
    
    void addedge(int u,int v,int c)
    {
        edges[edge].w=c,edges[edge].to=v,edges[edge].next=head[u],head[u]=edge++;
        //edges[edge].w=c,edges[edge].to=u,edges[edge].next=head[v],head[v]=edge++;
    }
    
    void unti_addedge(int u,int v,int c)
    {
        unti_edges[unti_edge].w=c,unti_edges[unti_edge].to=v,unti_edges[unti_edge].next=unti_head[u],unti_head[u]=unti_edge++;
        //unti_edges[unti_edge].w=c,unti_edges[unti_edge].to=u,unti_edges[unti_edge].next=unti_head[v],unti_head[v]=unti_edge++;
    }
    
    bool spfa(int node,int src,int head[],EDGE edges[],int dist[])
    {
        int i,l,r,u,v,w;
        bool visit[maxn];
        int q[maxn],outque[maxn];
        memset(visit,0,sizeof(visit));
        memset(outque,0,sizeof(outque));
        for (int i=0; i<=node; i++) dist[i]=INF;
        r=0;
        q[r++]=src;
        dist[src]=0;
        visit[src]=true;
        for (l=0; l!=r; ( (++l>=maxn)?(l=0):(1) ))
        {
            u=q[l];
            visit[u]=false;
            outque[u]++;
            if (outque[u]>node) return false;
            for (i=head[u]; i!=-1; i=edges[i].next)
            {
                v=edges[i].to;
                w=edges[i].w;
                if (dist[u]+w<dist[v])
                {
                    dist[v]=dist[u]+w;
                    if (visit[v]) continue;
                    q[r++]=v;
                    visit[v]=true;
                    if (r>=maxn) r=0;
                }
            }
        }
        return true;
    }
    
    int a_star(int start,int end,int n,int k,int head[],EDGE edges[],int dist[])
    {
        priority_queue<ANODE> que;
        ANODE u,v;
        int cnt=0;
        if (start==end) k++;
        if (dist[start]==INF) return -1;
        u.id=start;
        u.g=0;
        u.f=u.g+dist[u.id];
        que.push(u);
        while (!que.empty())
        {
            u=que.top();
            que.pop();
            if (u.id==end) cnt++;
            if (cnt==k) return u.g;
            for (int i=head[u.id]; i!=-1; i=edges[i].next)
            {
                v.id=edges[i].to;
                v.g=u.g+edges[i].w;
                v.f=v.g+dist[v.id];
                que.push(v);
            }
        }
        return -1;
    }
    
    int main()
    {
        int n,m,s,t,k;
        while (~scanf("%d%d",&n,&m))
        {
            prepare(n);
            while (m--)
            {
                int u,v,c;
                scanf("%d%d%d",&u,&v,&c);
                addedge(u,v,c);
                unti_addedge(v,u,c);
            }
            scanf("%d%d%d",&s,&t,&k);
            spfa(node,t,unti_head,unti_edges,dist);
            //spfa(node,t,head,edges,dist);
            int kthlength=a_star(s,t,node,k,head,edges,dist);
            printf("%d\n",kthlength);
        }
        return 0;
    }
    





  • 相关阅读:
    方法要求ref object参数, 如果传递double值?
    注册表获取exe位置+ Process类启动exe+参数让exe打开指定文件
    ArcEngine 实现SurfaceAnalysis中的Cut/Fill功能
    ArcEngine 3D extension has not been enabled .
    ArcEngine 实现 SurfaceAnalysis的Area/Volumn功能
    安装部署程序,将安装目录写入注册表
    About Death _Island
    73 Left(Lake DT) . Neophocaena phoconoides(江豚) 20120419
    判断是否安装客户端,没有安装则进行下载
    ArcEngine 没有Esri.ArcGis.GeoAnalyst 命名空间
  • 原文地址:https://www.cnblogs.com/cyendra/p/3038429.html
Copyright © 2011-2022 走看看