[Bzoj3875] [ahoi2014] The spfa of server guard games has a postactive motion regulation.

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Question:

First, a vertex can be split into multiple new vertices, thus having the foundation of the motion regulation on the graph.
That is, F [I] indicates the minimum cost of point I being eliminated. It can be updated by Split points.

However, this is post-efficient, so we use spfa to handle it.

Spfa post-effect dynamic regulation

Every time we update the dynamic value of point A, the dynamic value of several points may be updated.
That is, the points of vertex A can be split.
As a result, once the dynamic value of A is updated, the nodes will be added to the team.

All vertices should be queued at the beginning because they may be updated.

Code:

#include <queue>#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>#define N 201000#define M 2010000#define inf 0x3f3f3f3fusing namespace std;struct KSD{    int v,next;}e[M],E[M];int head[N],HEAD[N],cnt;inline void add(int u,int v){    e[++cnt].v=v;    E[cnt].v=u;    e[cnt].next=head[u];    E[cnt].next=HEAD[v];    HEAD[v]=head[u]=cnt;}long long A[N],dist[N];bool in[N];int n;queue<int>q;void spfa(){    while(!q.empty())q.pop();    int i,u,v;    for(i=1;i<=n;i++)q.push(i),in[i]=1;    while(!q.empty())    {        u=q.front(),q.pop(),in[u]=0;        long long temp=A[u];        for(i=head[u];i;i=e[i].next)            temp+=dist[e[i].v];        if(temp>=dist[u])continue;        dist[u]=temp;        for(i=HEAD[u];i;i=E[i].next)            if(!in[v=E[i].v])q.push(v),in[v]=1;    }}int main(){    int i,j,k;    int a,b,c;    scanf("%d",&n);    for(i=1;i<=n;i++)    {        cin>>A[i]>>dist[i]>>c;        while(c--)        {            scanf("%d",&a);            add(i,a);        }    }    spfa();    cout<<dist[1];    return 0;}

[Bzoj3875] [ahoi2014] The spfa of server guard games has a postactive motion regulation.