hdu2544最短路径spfa模版题

 

#include <cstdlib>
#include <iostream>
#include<vector>
#include<queue>
using namespace std;
struct edge
{
    int from,to,cost;
};
const int MAXN=111;
const int MAX=999999;
vector<edge>v[MAXN];
bool in_queue[MAXN];
int dist[MAXN];
void spfa(int p)
{
    queue<int>q;
    int i=0;
    memset(in_queue,0,sizeof(in_queue));
    for(i=0;i<=MAXN;i++)
    {
        dist[i]=MAX;
    }
    while(!q.empty())
    {
        q.pop();
    }
    dist[p]=0;
    q.push(p);
    in_queue[p]=1;
    while(!q.empty())
    {
        int cur=q.front();
        int i=0;
        q.pop();
        in_queue[cur]=0;
        for(i=0;i<=int(v[cur].size())-1;i++)
        {
            int cost=v[cur][i].cost+dist[cur];
            int to=v[cur][i].to;
            if(cost<dist[to])
            {
                dist[to]=cost;
                if(!in_queue[to])
                {
                    q.push(to);
                    in_queue[to]=1;
                }
            }
        }
    }
}

int main(int argc, char *argv[])
{
    int n,m;
    while((cin>>n>>m)&&(!((n==0)&&(m==0))))
    {
        int i=0;
        for(i=0;i<=n+1;i++)
        {
            v[i].clear();
        }
       
        while(m--)
        { 
            int from,to,cost;
            cin>>from>>to>>cost;
            edge e={from,to,cost};
            v[e.from].push_back(e);
            swap(e.from,e.to);
            v[e.from].push_back(e);
        }
        spfa(1);
        cout<<dist[n]<<endl;
    }
    //system("PAUSE");
    return EXIT_SUCCESS;
}