分层图最短路。边要开够。
#include<iostream> #include<cstdio> #include<cstring> #include<algorithm> #include<queue> #define maxv 300500 #define maxe 2000500 #define inf 2147483647 using namespace std; struct pnt { int x,y,id; }p[maxv]; struct edge { int v,w,nxt; }e[maxe]; int n,m,x,y,cnt=0,dis[maxv],nume=0,g[maxv],ans=inf; bool vis[maxv]; queue <int> q; void addpnt(int x,int y){cnt++;p[cnt].x=x;p[cnt].y=y;p[cnt].id=cnt;} bool cmp1(pnt x,pnt y){if (x.x==y.x) return x.y<y.y;return x.x<y.x;} bool cmp2(pnt x,pnt y){if (x.y==y.y) return x.x<y.x;return x.y<y.y;} void addedge(int u,int v,int w) { e[++nume].v=v; e[nume].w=w; e[nume].nxt=g[u]; g[u]=nume; } void spfa(int x) { while (!q.empty()) q.pop(); for (int i=1;i<=2*cnt;i++) vis[i]=false,dis[i]=inf; vis[x]=true;q.push(x);dis[x]=0; while (!q.empty()) { int head=q.front();q.pop(); for (int i=g[head];i;i=e[i].nxt) { int v=e[i].v; if (dis[v]>dis[head]+e[i].w) { dis[v]=dis[head]+e[i].w; if (!vis[v]) {vis[v]=true;q.push(v);} } } vis[head]=false; } } int main() { scanf("%d%d",&m,&n); for (int i=1;i<=n;i++) { scanf("%d%d",&x,&y); addpnt(x,y); } scanf("%d%d",&x,&y);addpnt(x,y); scanf("%d%d",&x,&y);addpnt(x,y); sort(p+1,p+cnt+1,cmp1); for (int i=1;i<=cnt-1;i++) { if (p[i].x==p[i+1].x) { addedge(p[i].id,p[i+1].id,(p[i+1].y-p[i].y)<<1); addedge(p[i+1].id,p[i].id,(p[i+1].y-p[i].y)<<1); } } sort(p+1,p+cnt+1,cmp2); for (int i=1;i<=cnt-1;i++) { if (p[i].y==p[i+1].y) { addedge(p[i].id+cnt,p[i+1].id+cnt,(p[i+1].x-p[i].x)<<1); addedge(p[i+1].id+cnt,p[i].id+cnt,(p[i+1].x-p[i].x)<<1); } } for (int i=1;i<=n;i++) { addedge(i,i+cnt,1); addedge(i+cnt,i,1); } spfa(n+1);ans=min(ans,dis[n+2]);ans=min(ans,dis[n+2+cnt]); spfa(n+1+cnt);ans=min(ans,dis[n+2]);ans=min(ans,dis[n+2+cnt]); if (ans==inf) printf("-1 "); else printf("%d ",ans); return 0; }