codevs 3290 华容道

HAHAHA

BFS+SPFA.

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<queue>
#define maxn 35
#define maxv 100500
#define maxe 400500
#define inf 100000007
using namespace std;
struct edge
{
    int v,w,nxt;
}e[maxe];
int n,m,qq,map[maxn][maxn],dp[maxn][maxn][],step[maxn][maxn][][],tot=,nume=,g[maxv],v[maxn][maxn][];
int dt[maxn][maxn],dx[]={-,,,},dy[]={,,-,},dis[maxv];
int ex,ey,sx,sy,tx,ty,s,t;
bool vis[maxv];
queue <int> q;
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 reset1()
{
    for (int i=;i<=n;i++)
        for (int j=;j<=m;j++)
            for (int k=;k<=;k++)
                for (int l=;l<=;l++)
                    step[i][j][k][l]=inf;
}
void reset2()
{
    for (int i=;i<=n;i++)
        for (int j=;j<=m;j++)
            dt[i][j]=inf;
}
void reset3()
{
    fill(dis+,dis+tot+,inf);
    memset(vis,false,sizeof(vis));
}
bool judge(int x,int y)
{
    if ((x>=) && (x<=n) && (y>=) && (y<=m) && (map[x][y]))
        return true;
    return false;
}
int bfs(int bx,int by,int tx,int ty)
{
    while (!q.empty()) q.pop();
    reset2();
    q.push(bx);q.push(by);
    dt[bx][by]=;
    while (!q.empty())
    {
        int hx=q.front();q.pop();
        int hy=q.front();q.pop();
        if ((hx==tx) && (hy==ty)) return dt[tx][ty];
        for (int i=;i<=;i++)
        {
            int rx=hx+dx[i],ry=hy+dy[i];
            if ((judge(rx,ry) && (dt[rx][ry]>dt[hx][hy]+)))
            {
                dt[rx][ry]=dt[hx][hy]+;
                q.push(rx);q.push(ry);
            }
        }
    }
    return inf;
}
void pre_bfs()
{
    reset1();
    for (int i=;i<=n;i++)
        for (int j=;j<=m;j++)
        {
            if (map[i][j])
            {
                map[i][j]=;
                for (int k=;k<=;k++)
                    for (int l=;l<=;l++)
                    {
                        int ax,ay,bx,by;
                        ax=i+dx[k];ay=j+dy[k];
                        bx=i+dx[l];by=j+dy[l];
                        if (judge(ax,ay) && judge(bx,by))
                        {
                            int r=bfs(ax,ay,bx,by);
                            if (r!=inf)
                                step[i][j][k][l]=r;
                        }
                    }
                map[i][j]=;
            }
        }
}
void pre_build()
{
    for (int i=;i<=n;i++)
        for (int j=;j<=m;j++)
        {
            if (judge(i,j))
            {
                for (int k=;k<=;k++)
                    for (int l=;l<=;l++)
                    {
                        int ax,ay,bx,by;
                        ax=i+dx[k];ay=j+dy[k];
                        bx=i+dx[l];by=j+dy[l];
                        if (judge(ax,ay) && (judge(bx,by)) && (step[i][j][k][l]!=inf))
                            addedge(v[i][j][k],v[bx][by][l^],step[i][j][k][l]+);
                    }
            }
        }
}
void build()
{
    s=++tot;t=++tot;
    for (int i=;i<=;i++)
    {
        if (judge(sx+dx[i],sy+dy[i]))
        {
            map[sx][sy]=;
            int r=bfs(ex,ey,sx+dx[i],sy+dy[i]);
            map[sx][sy]=;
            if (r!=inf)
                addedge(s,v[sx][sy][i],r);
        }
        if (judge(tx+dx[i],ty+dy[i]))
            addedge(v[tx][ty][i],t,);
    }
    map[sx][sy]=;
}
int spfa()
{
    if ((sx==tx) && (sy==ty)) return ;
    if ((sx==ex) && (sy==ey)) return -;
    if ((map[sx][sy]==) || (map[tx][ty]==)) return -;
    build();
    reset3();
    while (!q.empty()) q.pop();
    q.push(s);dis[s]=;vis[s]=true;
    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;
    }
    if (dis[t]==inf) return -;
    else return dis[t];
}
int main()
{
    memset(g,,sizeof(g));
    scanf("%d%d%d",&n,&m,&qq);
    for (int i=;i<=n;i++)
        for (int j=;j<=m;j++)
        {
            scanf("%d",&map[i][j]);
            for (int k=;k<=;k++)
                v[i][j][k]=++tot;
        }
    pre_bfs();
    pre_build();
    for (int i=;i<=qq;i++)
    {
        scanf("%d%d%d%d%d%d",&ex,&ey,&sx,&sy,&tx,&ty);
        printf("%d\n",spfa());
    }
    return ;
}