The first wave of the subject https://www.luogu.org/problem/P1119
This question we can ask then sorted by time corresponding with the inquiry will have been rebuilt successfully operating point
Each update a point to him as the starting point run again dijstra
Of course, this is not enough because adding a new point most likely to affect the short circuit between two other points
So after we finish dijstra also need to enumerate n square two points to see if they can short-circuit this point most updated
Doing a complexity point every update complexity is n ^ 2 + mlogn worst so the overall complexity is n ^ 3logn
Up to 200 n obvious complexity of the topic is reasonably practical assessment is up and running fast
#include<cstdio> #include<cstring> #include<algorithm> #include<queue> #include<cmath> using namespace std; const int M=507,inf=1e9+7; int read(){ int ans=0,f=1,c=getchar(); while(c<'0'||c>'9'){if(c=='-') f=-1; c=getchar();} while(c>='0'&&c<='9'){ans=ans*10+(c-'0'); c=getchar();} return ans*f; } int n,m,Q,wh[M]; struct node{int to,next,w;}e[M*M]; int first[M],cnt; void ins(int x,int y,int w){e[++cnt]=(node){y,first[x],w}; first[x]=cnt;} int dis[M][M],in[M],ans[M*M]; struct qaq{int x,y,id,T;}s[M*M]; int cmp(qaq x,qaq y){return x.T<y.T;} struct qwq{ int id,d; bool operator<(const qwq&x)const{return x.d<d;} }; priority_queue<qwq>q; void dj(int S){ in[S]=1; dis[S][S]=0; q.push((qwq){S,dis[S][S]}); while(!q.empty()){ qwq x=q.top(); q.pop(); if(dis[S][x.id]<x.d) continue; for(int i=first[x.id];i;i=e[i].next){ int now=e[i].to; if(!in[now]) continue; if(dis[S][now]>dis[S][x.id]+e[i].w){ dis[S][now]=dis[S][x.id]+e[i].w; q.push((qwq){now,dis[S][now]}); } } } for(int i=1;i<=n;i++)if(in[i]) dis[i][S]=dis[S][i]; for(int i=1;i<=n;i++)if(in[i]) for(int j=1;j<=n;j++)if(in[j]) if(dis[i][j]>dis[i][S]+dis[S][j]) dis[i][j]=dis[i][S]+dis[S][j]; } int main(){ int x,y,w,now=1; n=read(); m=read(); for(int i=1;i<=n;i++) for(int j=1;j<=n;j++)if(i!=j) dis[i][j]=inf; for(int i=1;i<=n;i++) wh[i]=read(),in[i]=0; for(int i=1;i<=m;i++) x=read()+1,y=read()+1,w=read(),ins(x,y,w),ins(y,x,w); Q=read(); for(int i=1;i<=Q;i++) s[i].x=read()+1,s[i].y=read()+1,s[i].T=read(),s[i].id=i; sort(s+1,s+1+Q,cmp); for(int i=1;i<=Q;i++){ while(now<=n&&wh[now]<=s[i].T) dj(now),now++; if((!in[s[i].x])||(!in[s[i].y])||(dis[s[i].x][s[i].y]==inf)) ans[s[i].id]=-1; else ans[s[i].id]=dis[s[i].x][s[i].y]; } for(int i=1;i<=Q;i++) printf("%d\n",ans[i]); return 0; }