分析
类似于点分治的思想,只统计经过分割线的最短路,然后把地图一分为二。
代码
#include <bits/stdc++.h>
#define rin(i,a,b) for(register int i=(a);i<=(b);++i)
#define irin(i,a,b) for(register int i=(a);i>=(b);--i)
#define trav(i,a) for(register int i=head[a];i;i=e[i].nxt)
typedef long long LL;
using std::cin;
using std::cout;
using std::endl;
inline int read(){
int x=0,f=1;char ch=getchar();
while(!isdigit(ch)){if(ch=='-')f=-1;ch=getchar();}
while(isdigit(ch)){x=x*10+ch-'0';ch=getchar();}
return x*f;
}
const int MAXN=200005;
int n,m,q,*r[MAXN],*c[MAXN],ans[MAXN];
int dis[MAXN];
int dx[4]={-1,1,0,0},dy[4]={0,0,-1,1};
bool vis[MAXN];
struct Qu{
int sx,sy,tx,ty,id;
}a[MAXN],b[MAXN];
struct Pair{
int pos,dis;
inline friend bool operator > (Pair x,Pair y){
return x.dis>y.dis;
}
};
std::priority_queue<Pair,std::vector<Pair>,std::greater<Pair> > pq;
inline int id(int x,int y){
return (x-1)*m+y;
}
void dijkstra(int sx,int sy,int sn,int tn,int sm,int tm){
rin(i,sn,tn) rin(j,sm,tm) dis[id(i,j)]=1e9,vis[id(i,j)]=false;
while(!pq.empty()) pq.pop();
dis[id(sx,sy)]=0;
pq.push((Pair){id(sx,sy),0});
while(!pq.empty()){
int idx=pq.top().pos;pq.pop();
if(vis[idx]) continue;
vis[idx]=true;
int x=(idx-1)/m+1,y=idx-(x-1)*m;
rin(i,0,3){
int xx=x+dx[i],yy=y+dy[i],w=0;
if(xx<sn||xx>tn||yy<sm||yy>tm||vis[id(xx,yy)]) continue;
if(i==0) w=c[xx][yy];
else if(i==1) w=c[x][y];
else if(i==2) w=r[xx][yy];
else w=r[x][y];
if(dis[id(xx,yy)]>dis[idx]+w){
dis[id(xx,yy)]=dis[idx]+w;
pq.push((Pair){id(xx,yy),dis[id(xx,yy)]});
}
}
}
}
void solve(int sn,int tn,int sm,int tm,int sq,int tq){
if(sn>tn||sm>tm||sq>tq) return;
if(tn-sn<tm-sm){
int mid=((sm+tm)>>1);
rin(i,sn,tn){
dijkstra(i,mid,sn,tn,sm,tm);
rin(j,sq,tq){
ans[a[j].id]=std::min(ans[a[j].id],
dis[id(a[j].sx,a[j].sy)]+dis[id(a[j].tx,a[j].ty)]);
}
}
int top=0;
rin(i,sq,tq) if(a[i].sy<mid&&a[i].ty<mid) b[++top]=a[i];
int temp=top;
rin(i,sq,tq) if(a[i].sy>mid&&a[i].ty>mid) b[++top]=a[i];
memcpy(a+sq,b+1,top*sizeof(Qu));
solve(sn,tn,sm,mid-1,sq,sq+temp-1);
solve(sn,tn,mid+1,tm,sq+temp,sq+top-1);
}
else{
int mid=((sn+tn)>>1);
rin(i,sm,tm){
dijkstra(mid,i,sn,tn,sm,tm);
rin(j,sq,tq){
ans[a[j].id]=std::min(ans[a[j].id],
dis[id(a[j].sx,a[j].sy)]+dis[id(a[j].tx,a[j].ty)]);
}
}
int top=0;
rin(i,sq,tq) if(a[i].sx<mid&&a[i].tx<mid) b[++top]=a[i];
int temp=top;
rin(i,sq,tq) if(a[i].sx>mid&&a[i].tx>mid) b[++top]=a[i];
memcpy(a+sq,b+1,top*sizeof(Qu));
solve(sn,mid-1,sm,tm,sq,sq+temp-1);
solve(mid+1,tn,sm,tm,sq+temp,sq+top-1);
}
}
int main(){
n=read(),m=read();
rin(i,1,n) r[i]=new int [m+5],c[i]=new int [m+5];
rin(i,1,n) rin(j,1,m-1) r[i][j]=read();
rin(i,1,n-1) rin(j,1,m) c[i][j]=read();
q=read();
rin(i,1,q){
a[i].sx=read();
a[i].sy=read();
a[i].tx=read();
a[i].ty=read();
a[i].id=i;
ans[i]=1e9;
}
solve(1,n,1,m,1,q);
rin(i,1,q) printf("%d\n",ans[i]);
return 0;
}