多源最短路问题

来源：互联网发布：桌面设置软件编辑：程序博客网时间：2024/06/16 10:19
数据范围1e5
具体看代码吧
#include<cmath>#include<ctime>#include<cstdio>#include<cstring>#include<cstdlib>#include<complex>#include<iostream>#include<algorithm>#include<iomanip>#include<vector>#include<string>#include<bitset>#include<queue>#include<map>#include<set>using namespace std;typedef long long ll;inline int read(){int x=0,f=1;char ch=getchar();while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}while(ch<='9'&&ch>='0'){x=(x<<1)+(x<<3)+ch-'0';ch=getchar();}return x*f;}void print(int x){if(x<0)putchar('-'),x=-x;if(x>=10)print(x/10);putchar(x%10+'0');}const int N=200100,inf=0X3f3f3f3f;int ecnt,last[N];struct EDGE{int to,nt,val;}e[N<<6];inline void add(int u,int v,int val){e[++ecnt]=(EDGE){v,last[u],val};last[u]=ecnt;}int n,m,K;ll ans;bool book[N],inq[N];ll dis[N][2],pre[N][2];int q[N];void spfa(){register int head=0,tail=0,i,j,u;memset(dis,0X3f,sizeof(dis));for(i=1;i<=n;++i)if(book[i]){for(j=last[i];j;j=e[j].nt)add(i+n,e[j].to,e[j].val);dis[i+n][0]=0;pre[i+n][0]=i;q[tail++]=i+n;inq[i+n]=1;}while(head<tail){u=q[head++];inq[u]=0;for(i=last[u];i;i=e[i].nt){if(dis[e[i].to][0]>dis[u][0]+e[i].val){if(pre[e[i].to][0]^pre[u][0]){dis[e[i].to][1]=dis[e[i].to][0];pre[e[i].to][1]=pre[e[i].to][0];}dis[e[i].to][0]=dis[u][0]+e[i].val;pre[e[i].to][0]=pre[u][0];if(!inq[e[i].to])q[tail++]=e[i].to,inq[e[i].to]=1;}else if(dis[e[i].to][1]>dis[u][0]+e[i].val&&pre[e[i].to][0]^pre[u][0]){dis[e[i].to][1]=dis[u][0]+e[i].val;pre[e[i].to][1]=pre[u][0];if(!inq[e[i].to])q[tail++]=e[i].to,inq[e[i].to]=1;}if(dis[e[i].to][1]>dis[u][1]+e[i].val&&pre[e[i].to][0]^pre[u][1]){dis[e[i].to][1]=dis[u][1]+e[i].val;pre[e[i].to][1]=pre[u][1];if(!inq[e[i].to])q[tail++]=e[i].to,inq[e[i].to]=1;}}}for(i=1;i<=n;++i)if(book[i]){pre[i][0]^i?ans=min(ans,dis[i][0]):ans=min(ans,dis[i][1]);}}int main(){n=read();m=read();K=read();register int i,u,v,val;for(i=1;i<=m;++i){u=read();v=read();val=read();add(u,v,val);}for(i=1;i<=K;++i)book[read()]=1;ans=inf;spfa();print(ans);puts("");return 0;}/*5 10 33 4 303 5 291 5 554 5 521 3 482 4 362 5 101 4 472 3 301 2 191 3 430*/
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