hdu 1874 最短路 优先队列+dijstra 最短路 1004题 1003题的变形

#include <iostream>#include <cstdio>#include <cstdlib>#include <cstring>#include <cmath>#include <algorithm>#include <set>#include <map>#include <vector>#include <queue>#include <ctime>using namespace std;const int N = 2000;const int INF = 1 << 30;struct Node{    int v,next,w;    bool operator < (const Node &a) const    {        return w > a.w;    }} Edge[N],t1,t2;int dis[N],vis[N],head[N],cnt;int res,ans;void addEdge(int u,int v,int w){    Edge[cnt].v = v;    Edge[cnt].next = head[u];    Edge[cnt].w = w;    head[u] = cnt++;}int dijstra(int  st,int ed){    priority_queue<Node> q;    for(int i = head[st] ; i != -1 ; i = Edge[i].next)    {        int v = Edge[i].v;        if(Edge[i].w<dis[v])        {            dis[v] = Edge[i].w;            t1.w = dis[v];            t1.v =  v;            q.push(t1);        }    }    dis[st]=0;//此句没加错了2次，囧~~~    vis[st] = 1;    while(!q.empty())    {        t1 = q.top();        q.pop();        int u = t1.v;        if(vis[u]) continue;        vis[u] = 1;       // res += dis[u];      //  ans=max(ans,dis[u]);        for(int i = head[u]; i != -1; i = Edge[i].next)        {            int v = Edge[i].v;            if(!vis[v] && dis[v]>dis[u]+Edge[i].w)            {                dis[v] =dis[u]+Edge[i].w;                t2.v = v;                t2.w = dis[v];                q.push(t2);            }        }    }    if(dis[ed]==INF)return -1;    return dis[ed];}int main(){    int n,m,st,ed;    while(scanf("%d%d",&n,&m)!=EOF)    {        memset(head,-1,sizeof(head));        memset(vis,0,sizeof(vis));        int u,v,w;        cnt=0;        for(int j=1; j<=m; j++)        {            cin>>u>>v>>w;            u++,v++;            addEdge(u,v,w);            addEdge(v,u,w);        }        scanf("%d%d",&st,&ed);        for(int i = 0 ; i <=n+1;  i ++) dis[i] = INF;        res=dijstra(st+1,ed+1);        printf("%d\n",res);    }    return 0;}/*7 91 2 281 6 102 7 142 3 166 5 257 5 247 4 183 4 125 4 22*/