POJ-1511 Invitation Cards(最短路)

//求源点a和到所有点b的a->b的最短路+b->a的最短路之和  正向反向各dj一次  数组开小TLE1,没开longlong WA1 加读入挂快1000ms
#include <cstdio>
#include <algorithm>
#include <queue>
#include <cstring>
#include <cmath>
using namespace std;
typedef pair<int,int> PII;
const int MAXN=1e6+7;
const int MAXM=1e6+7;
const int INF=0x3f3f3f3f;
int head[MAXN<<1],to[MAXM<<1],ne[MAXM<<1],wt[MAXM<<1],n,m,dist[MAXN<<1],ecnt,T;
inline int read(){
int x=0; bool f=0; char ch=getchar();
while (ch<'0'||'9'<ch) f|=ch=='-', ch=getchar();
while ('0'<=ch && ch<='9') x=x*10+ch-'0', ch=getchar();
return f?-x:x;
}
void init()
{
ecnt=0;
memset(head,0,sizeof(head));
}
void addedge(int a,int b,int c)
{
ne[++ecnt]=head[a];
head[a]=ecnt;
to[ecnt]=b;
wt[ecnt]=c;
}
int vis[MAXN<<1];
priority_queue<PII> pq;
void dijkstra(int s,int mode)//s为源点
{
for(int i=1; i<=n; i++)
dist[i+mode]=INF,vis[i+mode]=0;
dist[s+mode]=0;
pq.push(PII(0,s+mode));
while(!pq.empty())
{
int fr=pq.top().second;
pq.pop();
if(vis[fr])continue;
vis[fr]=1;
for(int k=head[fr]; k; k=ne[k])
{
int v=to[k];
if(dist[v]>dist[fr]+wt[k])
{
dist[v]=dist[fr]+wt[k];
pq.push(PII(-dist[v],v));
}
}
}
}
int main()
{
int ta,tb,tc;
T=read();
while(T--)
{
n=read();
m=read();
init();
for(int i=1; i<=m; i++)
{
ta=read(),tb=read(),tc=read();
addedge(ta,tb,tc);
addedge(tb+n,ta+n,tc);
}
long long ans=0;
dijkstra(1,0);
dijkstra(1,n);
for(int i=1; i<=2*n; i++)
ans+=dist[i];
printf("%lld\n",ans);
}
return 0;
}