hdu1535 SPFA
2边SPFA 然后求和
#include<stdio.h> #include<string.h> #include<queue> #define INF 1000000000 #define ii __int64 using namespace std; struct node { ii v; ii val; ii next; }edge1[1000003],edge2[1000003]; ii head1[1000003],dis1[1000003],head2[1000003],dis2[1000003],vis[1000003]; ii n,m,t,index1,index2; void add1(ii x,ii y,ii z) { ii i,j; edge1[index1].v=y; edge1[index1].val=z; edge1[index1].next=head1[x]; head1[x]=index1++; } void add2(ii x,ii y,ii z) { ii i,j; edge2[index2].v=y; edge2[index2].val=z; edge2[index2].next=head2[x]; head2[x]=index2++; } void SPFA1(ii u) { ii i,j; memset(vis,0,sizeof(vis)); queue<ii>q; for(i=1;i<=n;i++) dis1[i]=INF; dis1[u]=0; vis[u]=1; q.push(u); while(!q.empty()) { ii v=q.front(); q.pop(); vis[v]=0; for(i=head1[v];i!=-1;i=edge1[i].next) { ii tmp=edge1[i].v; if(dis1[tmp]>dis1[v]+edge1[i].val) { dis1[tmp]=dis1[v]+edge1[i].val; if(!vis[tmp]) { q.push(tmp); vis[tmp]=1; } } } } } void SPFA2(ii u) { ii i,j; memset(vis,0,sizeof(vis)); queue<ii>q; for(i=1;i<=n;i++) dis2[i]=INF; dis2[u]=0; vis[u]=1; q.push(u); while(!q.empty()) { ii v=q.front(); q.pop(); vis[v]=0; for(i=head2[v];i!=-1;i=edge2[i].next) { ii tmp=edge2[i].v; if(dis2[tmp]>dis2[v]+edge2[i].val) { dis2[tmp]=dis2[v]+edge2[i].val; if(!vis[tmp]) { q.push(tmp); vis[tmp]=1; } } } } } int main() { ii i,j,t,m; scanf("%I64d",&t); while(t--) { scanf("%I64d%I64d",&n,&m); index1=index2=1; memset(dis1,0,sizeof(dis1)); memset(head1,-1,sizeof(head1)); memset(dis2,0,sizeof(dis2)); memset(head2,-1,sizeof(head2)); for(i=0;i<m;i++) { ii x,y,z; scanf("%I64d%I64d%I64d",&x,&y,&z); add1(x,y,z); add2(y,x,z); } SPFA1(1); /*for(i=1;i<=n;i++) printf("%d ",dis1[i]); printf("\n");*/ SPFA2(1); /*for(i=1;i<=n;i++) printf("%d ",dis2[i]);printf("\n");*/ ii ans=0; for(i=1;i<=n;i++) { ans+=dis1[i]+dis2[i]; } printf("%I64d\n",ans); } }