最短路（模板

刘汝佳

#include<cstdio>
#include<cstring>
#include<vector>
#include<algorithm>
#include<queue>
using namespace std;
#define INF 1e8
const int maxn = 200+10;
int n,m;
struct Edge
{
    int from,to,dist;
    Edge(int f,int t,int d):from(f),to(t),dist(d){}
};
 
struct HeapNode
{
    int d,u;
    HeapNode(int d,int u):d(d),u(u){}
    bool operator< (const HeapNode &rhs)const
    {
        return d > rhs.d;
    }
};
 
struct Dijkstra
{
    int n,m;
    vector<Edge> edges;
    vector<int> G[maxn];
    bool done[maxn];
    int d[maxn];
 
    void init(int n)
    {
        this->n=n;
        for(int i=0;i<n;i++) G[i].clear();
        edges.clear();
    }
 
    void AddEdge(int from,int to,int dist)
    {
        edges.push_back(Edge(from,to,dist));
        m = edges.size();
        G[from].push_back(m-1);
    }
 
    int dijkstra(int s,int e)
    {
        priority_queue<HeapNode> Q;
        for(int i=0;i<n;i++) d[i]=INF;
        d[s]=0;
        Q.push(HeapNode(d[s],s));
        memset(done,0,sizeof(done));
 
        while(!Q.empty())
        {
            HeapNode x= Q.top(); Q.pop();
            int u =x.u;
            if(done[u]) continue;
            done[u]=true;
 
            for(int i=0;i<G[u].size();i++)
            {
                Edge &e=edges[G[u][i]];
                if(d[e.to] > d[u]+e.dist)
                {
                    d[e.to] = d[u]+e.dist;
                    Q.push(HeapNode(d[e.to],e.to));
                }
            }
        }
        if(d[e] == INF)
            return -1;
        return d[e];
    }
}DJ;
 
int main()
{
    while(scanf("%d%d",&n,&m)==2)
    {
        DJ.init(n);
        for(int i=0;i<m;i++)
        {
            int u,v,d;
            scanf("%d%d%d",&u,&v,&d);
            DJ.AddEdge(u,v,d);
            DJ.AddEdge(v,u,d);
        }
        int s,e;
        scanf("%d%d",&s,&e);
        printf("%d
",DJ.dijkstra(s,e) );
    }
    return 0;
}

 第一：建图

第二：