zju 1003. Emergency (25)

http://pat.zju.edu.cn/contests/pat-a-practise/1003

最短路

代码：

#include<iostream>

#include<cstdio>

#include<cstring>

#include<cmath>

#include<algorithm>

#include<vector>

#include<set>

#include<map>

#include<string>

#include<queue>

#include<stack>

#include <iomanip>

using namespace std;

#define LL long long

const double eps=1e-6;

const int INF=0x3f3f3f3f;

const int N=505;

int road[N][N];

int a[N];

int dist[N];

int num[N];

int teams[N];

bool had[N];

void dijkstra(int n,int c1,int c2)

{

    for(int i=0;i<n;++i)

    dist[i]=INF;

    memset(num,0,sizeof(num));

    memset(teams,0,sizeof(teams));

    memset(had,false,sizeof(had));

    teams[c1]=a[c1];

    num[c1]=1;

    dist[c1]=0;

    for(int w=0;w<n;++w)

    {

        int k=-1;

        for(int i=0;i<n;++i)

        if(!had[i]&&(k==-1||dist[i]<dist[k]))

        k=i;



        if(k==c2)

        break;

        had[k]=true;

        for(int i=0;i<n;++i)

        if(!had[i])

        {

            if(dist[i]>dist[k]+road[k][i])

            {

                dist[i]=dist[k]+road[k][i];

                num[i]=num[k];

                teams[i]=a[i]+teams[k];

            }else if(dist[i]==dist[k]+road[k][i])

            {

                num[i]+=num[k];

                if(teams[i]<a[i]+teams[k])

                teams[i]=a[i]+teams[k];

            }

        }

    }

}

int main()

{

    //freopen("data.in","r",stdin);

    int n,m,c1,c2;

    while(cin>>n>>m>>c1>>c2)

    {

        for(int i=0;i<N;++i)

        for(int j=0;j<N;++j)

        road[i][j]=INF;

        for(int i=0;i<n;++i)

        cin>>a[i];

        while(m--)

        {

            int l,r,k;

            cin>>l>>r>>k;

            road[l][r]=road[r][l]=min(road[l][r],k);

        }

        dijkstra(n,c1,c2);

        cout<<num[c2]<<" "<<teams[c2]<<endl;

    }

    return 0;

}