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2020-01-19 12:25:00
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直接按照规则建图后跑最短路

#include<bits/stdc++.h>
namespace ZDY{
    #pragma GCC optimize(3)
    #define il __inline__ __attribute__ ((always_inline))
    #define register
    #define ll long long
    #define ull unsigned long long
    #define db double
    #define sht short
    #define MB template <class T>il
    #define Fur(i,x,y) for(int i(x);i<=y;++i)
    #define Fdr(i,x,y) for(int i(x);i>=y;--i)
    #define fl(i,x) for(int i(head[x]),to;to=e[i].to,i;i=e[i].nxt)
    #define clr(x,y) memset(x,y,sizeof(x))
    #define cpy(x,y) memcpy(x,y,sizeof(x))
    #define fin(s) freopen(s".in","r",stdin)
    #define fout(s) freopen(s".out","w",stdout)
    #define fcin ios::sync_with_stdio(false)
    #define l2(n) ((int)(log2(n)))
    #define inf 2122219134
    MB T ABS(T x){return x>0?x:-x;}
    MB T MAX(T x,T y){return x>y?x:y;}
    MB T MIN(T x,T y){return x<y?x:y;}
    MB T GCD(T x,T y){return y?GCD(y,x%y):x;}
    MB void SWAP(T &x,T &y){T t=x;x=y;y=t;}
}using namespace ZDY;using namespace std;
namespace IO{const int str=1<<20;static char in_buf[str],*in_s,*in_t;bool __=0;il char gc(){return (in_s==in_t)&&(in_t=(in_s=in_buf)+fread(in_buf,1,str,stdin)),in_s==in_t?__=1,EOF:*in_s++;}il void in(string &ch){ch.clear();if(__)return;char c;while((c=gc())!=EOF&&isspace(c));if(c==EOF){__=1;return;}ch+=c;while((c=gc())!=EOF&&!isspace(c))ch+=c;if(c==EOF)__=1;}il void in(char &ch){if(__)return;char c;while((c=gc())!=EOF&&isspace(c));if(c==EOF)__=1;else ch=c;}il void in(char *ch){*ch='\0';if(__)return;char c;while((c=gc())!=EOF&&isspace(c));if(c==EOF){__=1;return;}*ch=c;ch++;while((c=gc())!=EOF&&!isspace(c))*ch=c,ch++;if(c==EOF)__=1;*ch='\0';}template<typename T>il void in(T &x){if(__)return;char c=gc();bool f=0;while(c!=EOF&&(c<'0'||c>'9'))f^=(c=='-'),c=gc();if(c==EOF){__=1;return;}x=0;while(c!=EOF&&'0'<=c&&c<='9')x=x*10+c-48,c=gc();if(c==EOF)__=1;if(f)x=-x;}template<typename T,typename ... arr>il void in(T &x,arr & ... y){in(x),in(y...);}const char ln='\n';static char out_buf[str],*out_s=out_buf,*out_t=out_buf+str;il void flush(){fwrite(out_buf,1,out_s-out_buf,stdout);out_s=out_buf;}il void pt(char c){(out_s==out_t)?(fwrite(out_s=out_buf,1,str,stdout),*out_s++=c):(*out_s++=c);}il void out(const char* s){while(*s)pt(*s++);}il void out(char* s){while(*s)pt(*s++);}il void out(char c){pt(c);}il void out(string s){for(int i=0;s[i];i++)pt(s[i]);}template<typename T>il void out(T x){if(!x){pt('0');return;}if(x<0)pt('-'),x=-x;char a[50],t=0;while(x)a[t++]=x%10,x/= 10;while(t--)pt(a[t]+'0');}template<typename T,typename ... arr>il void out(T x,arr & ... y){out(x),out(y...);}}using namespace IO;
int n,m,cnt=0,head[511*511],dx[4]={0,1,0,-1},dy[4]={1,0,-1,0},sx,sy,tx,ty,d[511*511];
char a[511][511];
struct edge{
    int to,nxt,w;
}e[511*511*10];
il void add(int x,int y,int w){
    e[++cnt].to=y;e[cnt].nxt=head[x];head[x]=cnt;e[cnt].w=w;
}
il int id(int x,int y){return (x-1)*m+y;}
struct cmp{
    bool operator()(int x,int y){
        return d[x]>d[y];
    }
};
bool v[511*511];
priority_queue<int,vector<int>,cmp>q;
void bfs(){
    d[id(sx,sy)]=1;
    q.push(id(sx,sy));
    while(!q.empty()){
        int x=q.top();q.pop();v[x]=0;
        fl(i,x)if(d[x]+e[i].w<d[to]||!d[to]){
            d[to]=d[x]+e[i].w;
            if(!v[to])v[to]=1,q.push(to);
        }
    }
}
int main(){
    in(n,m);
    Fur(i,1,n)in(a[i]+1);
    Fur(i,1,n)Fur(j,1,m)
        if(a[i][j]=='C')sx=i,sy=j;
        else if(a[i][j]=='F')tx=i,ty=j;
    Fur(i,1,n)Fur(j,1,m)
    if(a[i][j]!='#')
    Fur(t,0,3){
        int x=i+dx[t],y=j+dy[t];
        if(x<1||x>n||y<1||y>m||a[x][y]=='#')continue;
        add(id(i,j),id(x,y),1);
    }
    Fur(i,1,n)Fur(j,1,m)
    if(a[i][j]!='#'){
        int dis=inf,x,y,tt=0,p[4],tot=0;
        Fur(t,0,3){
            x=i,y=j,tt=0;
            while(a[x][y]!='#'){
                x+=dx[t],y+=dy[t],++tt;
                if(x<1||x>n||y<1||y>m){tt=inf;break;}
            }
            x-=dx[t],y-=dy[t];
            if(tt!=inf)dis=MIN(dis,tt),p[tot++]=id(x,y);
        }
        if(dis!=inf)
        Fur(t,0,tot-1)add(id(i,j),p[t],dis);
    }
    bfs();
    if(!d[id(tx,ty)])printf("nemoguce\n");
    else printf("%d\n",d[id(tx,ty)]-1);
}
LG 4442 [COCI2017-2018t3]-Portal
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