zju 1003. Emergency (25) 夜

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;
}