(简单) POJ 1797 Heavy Transportation，Dijkstra。

#include<iostream>
#include<cstring>
#include<queue>
#include<vector>
#include<cstdio>

#define min(a,b) (a<b ? a:b)

using namespace std;

const int INF=10e8;
const int MaxN=1010;

struct Node
{
    int v,val;

    Node(int _v=0,int _val=0):v(_v),val(_val) {}
    bool operator < (const Node &a) const
    {
        return val<a.val;
    }
};

struct Edge
{
    int v,cost;

    Edge(int _v=0,int _cost=0):v(_v),cost(_cost) {}
};

vector <Edge> E[MaxN];

void Dijkstra(int lowcost[],int n,int start)
{
    priority_queue <Node> que;
    Node qtemp;
    int len;
    int u,v,cost;

    for(int i=1;i<=n;++i)
    {
        lowcost[i]=0;
    }
    lowcost[start]=INF;

    que.push(Node(start,INF));

    while(!que.empty())
    {
        qtemp=que.top();
        que.pop();

        u=qtemp.v;



        len=E[u].size();

        for(int i=0;i<len;++i)
        {
            v=E[u][i].v;
            cost=E[u][i].cost;

            if(min(cost,lowcost[u])>lowcost[v])
            {
                lowcost[v]=min(cost,lowcost[u]);
                que.push(Node(v,lowcost[v]));
            }
        }
    }
}

inline void addEdge(int u,int v,int c)
{
    E[u].push_back(Edge(v,c));
}

int ans[MaxN];

int main()
{
//    ios::sync_with_stdio(false);

    int N,M;
    int a,b,c;
    int T;

    scanf("%d",&T);

    for(int cas=1;cas<=T;++cas)
    {
        scanf("%d %d",&N,&M);

        for(int i=1;i<=N;++i)
            E[i].clear();

        for(int i=1;i<=M;++i)
        {
            scanf("%d %d %d",&a,&b,&c);

            addEdge(a,b,c);
            addEdge(b,a,c);
        }

        Dijkstra(ans,N,1);

        printf("Scenario #%d:\n",cas);
        printf("%d\n\n",ans[N]);
    }

    return 0;
}