【模拟7.22】光（模拟）

一道非常考验码力的题，快崩溃了，码了一晚上，刚想着再A不掉就弃了，离下课还剩三分钟突然A掉了，

考试时码了两百行大模拟，因为统计答案错了导致WA0，考完一改就60...........

推荐阅读同机房大佬WD的博客

自己没啥可讲的，主要是学了学set的用法，set可以支持lower_bound操作，

然后各种转向，判断.........我就不细说了

还有统计开始的起点的光线长度时我没想好怎么处理，于是我先让光线射一次，让它到达边缘，

让这条边标记为-1（为了使它重复经过），然后还有ans=-1;为了排除到达点的影响（可能有点乱，还是看代码吧）。

考试代码（60分）

#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<algorithm>
#include<cmath>
#include<stack>
#include<vector>
#include<queue>
#define MAXN 5101
#define ps push_back
#define ll long long
using namespace std;
int bian[MAXN*MAXN];
int ans;int n,m,p;
struct node{int l;int r;int data;int lazy;}e[MAXN*MAXN];
int pan_quan(int x,int dir)
{
    if(dir==1)//向右下
    {
        if(e[x+1].lazy==1&&e[x+m].lazy==1&&e[x+m+1].lazy==1)
        {
           return 1;
        }
        else if(e[x+m+1].lazy==1)
        {
            if(e[x+1].lazy==0&&e[x+m].lazy==0)
            {
                return 1;
            }
        }
        return 0;
    }
    else if(dir==4)//向左上
    {
        if(e[x-1].lazy==1&&e[x-m].lazy==1&&e[x-m-1].lazy==1)
        {
           return 1;
        }
        else if(e[x-m-1].lazy==1)
        {
           if(e[x-1].lazy==0&&e[x-m].lazy==0)
           {
                return 1;
           }
        }
        return 0;
    }
    else if(dir==2)//向左下
    {
        if(e[x-1].lazy==1&&e[x-1+m].lazy==1&&e[x+m].lazy==1)
        {
           return 1;
        }
        else if(e[x+m-1].lazy==1)
        {
             if(e[x-1].lazy==0&&e[x+m].lazy==0)
             {
                 return 1;
             }           
        }
        return 0;
    }
    else if(dir==3)//向右上
    {
        if(e[x+1].lazy==1&&e[x+1-m].lazy==1&&e[x-m].lazy==1)
        {
           return 1;
        }
        else if(e[x+1-m].lazy==1)
        {
             if(e[x+1].lazy==0&&e[x-m].lazy==0)
             {
                 return 1;
             }
        }
        return 0;
    }
}
int th=0;int ta=0;
int pan_hang(int x,int dir)
{
    th=0;ta=0;
    if(dir==1)//向右下
    {
        if(e[x+m].lazy==1&&e[x+m+1].lazy==1)
        {
           th=x+1;ta=3;
           return x+1;
        }
        return 0;
    }
    else if(dir==4)//向左上
    {
        if(e[x-m].lazy==1&&e[x-m-1].lazy==1)
        {
           th=x-1;ta=2;
           return x-1;
        }
        return 0;
    }
    else if(dir==2)//向左下
    {
        if(e[x-1+m].lazy==1&&e[x+m].lazy==1)
        {
           th=x-1;ta=4;
           return x-1;
        }
        return 0;
    }
    else if(dir==3)//向右上
    {
        if(e[x+1-m].lazy==1&&e[x-m].lazy==1)
        {
           th=x+1;ta=1;
           return x+1;
        }
        return 0;
    }
}
int pan_lie(int x,int dir)
{
    th=0;ta=0;
    if(dir==1)//向右下
    {
        if(e[x+1].lazy==1&&e[x+m+1].lazy==1)
        {
           th=x+m;ta=2;
           return 1;
        }
        return 0;
    }
    else if(dir==4)//向左上
    {
        if(e[x-1].lazy==1&&e[x-m-1].lazy==1)
        {
           th=x-m;ta=3;
           return 1;
        }
        return 0;
    }
    else if(dir==2)//向左下
    {
        if(e[x-1+m].lazy==1&&e[x-1].lazy==1)
        {
           th=x+m;ta=1;
           return 1;
        }
        return 0;
    }
    else if(dir==3)//向右上
    {
        if(e[x+1-m].lazy==1&&e[x+1].lazy==1)
        {
           th=x-m;ta=4;
           return 1;
        }
        return 0;
    }
}
void DFS(int x,int dir,int l,int r)
{
    if(bian[x]==3)
    {
        return ;
    }
    bian[x]++;
    if(pan_quan(x,dir)==1)
    {
        if(bian[x]==1)ans++;
        DFS(x,5-dir,l,r);
    }
    else if(pan_hang(x,dir)!=0)
    {
        if(bian[x]==1)ans++;
        DFS(th,ta,e[th].l,e[th].r);
    }
    else if(pan_lie(x,dir)!=0)
    {
        if(bian[x]==1)ans++;
        DFS(th,ta,e[th].l,e[th].r);
    }
    else  
    {
        if(dir==1)x+=m+1;
        if(dir==4)x-=m+1;
        if(dir==2)x=x-1+m;
        if(dir==3)x=x-m+1;
        if(bian[x]==1)ans++;
        DFS(x,dir,e[x].l,e[x].r);
    }
    return ;
}
int kuan[MAXN][MAXN];
int main()
{
   scanf("%d%d%d",&n,&m,&p);
   for(int i=1;i<=p;++i)
   {
      int x,y;
      scanf("%d%d",&x,&y);
      kuan[x][y]=1;
   }  
   int xx,yy;
   scanf("%d%d",&xx,&yy);
   string s;
   cin>>s;
   int fir=0,root;
   for(int i=0;i<=n+1;++i)
   {
       for(int j=0;j<=m+1;++j)
       {
           int da=(i*(m+2)+j+1);
           e[da].data=da;
           e[da].l=i;e[da].r=j;
           e[da].lazy=kuan[i][j];
           if(i==0||i==n+1||j==0||j==m+1)
           {
              e[da].lazy=1;
           }
           if(i==xx&&j==yy)
           {
              root=da;
           }
       }
   }
   n+=2;m+=2;
   if(s[0]=='N'&&s[1]=='E')fir=3;
   else if(s[0]=='N'&&s[1]=='W')fir=1;
   else if(s[0]=='S'&&s[1]=='E')fir=4;
   else if(s[0]=='S'&&s[1]=='W')fir=2;
   DFS(root,fir,e[root].l,e[root].r);
   printf("%d
",ans);
}

AC代码

#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<algorithm>
#include<cmath>
#include<stack>
#include<vector>
#include<queue>
#include<set>
#include<map>
#define MAXN 1000001
#define ps push_back
#define ll long long
using namespace std;
ll n,m,k,ch,fir;ll bian[MAXN][5];
ll x,y;
map<pair<ll,ll>,bool>h;
set<ll>v1[MAXN];set<ll>v2[MAXN];//1：左上（1）右下（4）x+y定值 2：左下（2）右上（3）x-y+m定值
ll find_qian1(ll k,ll x)//4 右下
{
    set<ll>::iterator it;it=v1[k].lower_bound(x);return *it;
}
ll find_hou1(ll k,ll x)//1 左上
{
    set<ll>::iterator it;it=v1[k].lower_bound(x);;it--;return *it;//printf("it=%lld
",*it);
}
ll find_qian2(ll k,ll x)//3 右上
{
    set<ll>::iterator it;it=v2[k].lower_bound(x);it--;return *it;
}
ll find_hou2(ll k,ll x)//2 左下
{
    set<ll>::iterator it;it=v2[k].lower_bound(x);return *it;
}
ll find1(ll x,ll y)
{
    return x-y+ch;
}
ll find2(ll x,ll y)
{
    return x+y;
}
ll nxt;ll ans=0;ll xxx=0,yyy=0;
map<pair<ll,ll>,bool>star;ll bbb=0;
int main()
{  
    scanf("%lld%lld%lld",&n,&m,&k);
    ch=m+n+2;
    for(ll i=1;i<=k;++i)
    {
        ll x,y;
        scanf("%lld%lld",&x,&y);
        v1[find1(x,y)].insert(x);     v2[find2(x,y)].insert(x);
        h[make_pair(x,y)]=1;
    }
    for(ll i=0;i<=n+1;++i)
    {
        v1[find1(i,0)].insert(i);     v2[find2(i,0)].insert(i);
        v1[find1(i,m+1)].insert(i);   v2[find2(i,m+1)].insert(i);
        h[make_pair(i,0)]=1;          h[make_pair(i,m+1)]=1;
    }
    for(ll j=1;j<=m;++j)
    {
        v1[find1(0,j)].insert(0);     v2[find2(0,j)].insert(0);
        v1[find1(n+1,j)].insert(n+1); v2[find2(n+1,j)].insert(n+1);
        h[make_pair(0,j)]=1;          h[make_pair(n+1,j)]=1;
    }
    scanf("%lld%lld",&x,&y);
    string s;cin>>s;
    if(s[0]=='N'&&s[1]=='E')fir=3;
    else if(s[0]=='N'&&s[1]=='W')fir=4;
    else if(s[0]=='S'&&s[1]=='E')fir=1;
    else if(s[0]=='S'&&s[1]=='W')fir=2;   
    if(fir==1)
    {
         nxt=find_hou1(find1(x,y),x);
         ans-=1;//abs(nxt-x);
         nxt++;//向左移
         y=nxt-x+y;x=nxt;
         bian[find1(x,y)][fir]=-1;
         //xxx=x;yyy=y;
    }
    else if(fir==4)
    {
         nxt=find_qian1(find1(x,y),x);
         ans-=1;//abs(nxt-x);
         nxt--;
         y=nxt-x+y;x=nxt;
         bian[find1(x,y)][fir]=-1;
         //xxx=x;yyy=y;
    }
    else if(fir==2)
    {
         nxt=find_hou2(find2(x,y),x);
         ans-=1;//abs(nxt-x);
         nxt--;
         y=x+y-nxt;x=nxt;
         bian[find2(x,y)][fir]=-1;
         //xxx=x;yyy=y;
    }
    else if(fir==3)
    {
         nxt=find_qian2(find2(x,y),x);
         ans-=1;//abs(nxt-x);
         nxt++;
         y=x+y-nxt;x=nxt;
         bian[find2(x,y)][fir]=-1;
         //xxx=x;yyy=y;
    }
    ll tiao=0;bool pan=0;
    //printf("x=%lld y=%lld fir=%lld
",x,y,fir);
    while(1)//1：左上（1）右下（4）x+y定值      2：左下（2）右上（3）x-y+m定值
    {
        ++tiao;
        //if(tiao<=20)
        //printf("x===%lld y===%lld fir===%lld
",x,y,fir);  
        /*if(tiao>2)
        {
            if(x==xxx&&y==yyy)
            {
                pan=1;break;
            }
        } */  
        if(fir==1)
        {
            if(pan==1)break;
            if(bian[find1(x,y)][fir]>=1){pan=1;break;}
            nxt=find_hou1(find1(x,y),x);
            //ll nxt_x=nxt,nxt_y=x+y-nxt_x;
            ll nxt_x=nxt,nxt_y=nxt_x-x+y;
            bian[find1(x,y)][fir]++;
            //cout<<bian[find1(x,y)][fir]<<endl;
            //printf("xxx%lld yyy%lld
",nxt_x,nxt_y);
            if(bian[find1(x,y)][5-fir]==0)ans+=abs(nxt_x-x);
            //printf("ans=%lld
",ans);
            if(h[make_pair(nxt_x+1,nxt_y)]&&h[make_pair(nxt_x,nxt_y+1)])
            {                
                fir=5-fir;
                x=nxt_x+1;y=nxt_y+1;                  
            }
            else if(h[make_pair(nxt_x+1,nxt_y)])
            {
                fir=3;
                x=nxt_x;y=nxt_y+1;
            }
            else if(h[make_pair(nxt_x,nxt_y+1)])
            {
                fir=2;
                x=nxt_x+1;y=nxt_y;
            }
            else
            {
                fir=5-fir;
                x=nxt_x+1;y=nxt_y+1;  
            }
            if(tiao==1)xxx=x,yyy=y;
            //printf("修改x===%lld y==%lld fir==%lld
",x,y,fir);
        }     
        else if(fir==4)
        {
            if(pan==1)break;
            if(bian[find1(x,y)][fir]>=1){pan=1;break;}
            nxt=find_qian1(find1(x,y),x);
            ll nxt_x=nxt,nxt_y=nxt_x-x+y;
            bian[find1(x,y)][fir]++;
            //printf("%lld
",bian[find1(x,y)][5-fir]);
            if(bian[find1(x,y)][5-fir]==0)ans+=abs(nxt_x-x);
            //printf("nn=%lld
",nxt_x);
            //printf("ans=%lld
",ans);
            if(h[make_pair(nxt_x-1,nxt_y)]&&h[make_pair(nxt_x,nxt_y-1)])
            {                
                fir=5-fir;
                x=nxt_x-1;y=nxt_y-1;                  
            }
            else if(h[make_pair(nxt_x-1,nxt_y)])
            {
                fir=2;
                x=nxt_x;y=nxt_y-1;
            }
            else if(h[make_pair(nxt_x,nxt_y-1)])
            {
                fir=3;
                x=nxt_x-1;y=nxt_y;
            }
            else
            {
                fir=5-fir;
                x=nxt_x-1;y=nxt_y-1;  
            }
            if(tiao==1)xxx=x,yyy=y;
        }
        else if(fir==2)//2：左下（2）右上（3）x-y+m定值
        {
            if(pan==1)break;
            if(bian[find2(x,y)][fir]>=1){pan=1;break;}
            nxt=find_hou2(find2(x,y),x);
            ll nxt_x=nxt,nxt_y=x+y-nxt_x;
            bian[find2(x,y)][fir]++;
            if(bian[find2(x,y)][5-fir]==0)ans+=abs(nxt_x-x);
            if(h[make_pair(nxt_x-1,nxt_y)]&&h[make_pair(nxt_x,nxt_y+1)])
            {                
                fir=5-fir;
                x=nxt_x-1;y=nxt_y+1;                  
            }
            else if(h[make_pair(nxt_x-1,nxt_y)])
            {
                fir=4;
                x=nxt_x;y=nxt_y+1;
            }
            else if(h[make_pair(nxt_x,nxt_y+1)])
            {
                fir=1;
                x=nxt_x-1;y=nxt_y;
            }
            else
            {
                fir=5-fir;
                x=nxt_x-1;y=nxt_y+1;  
            }
            if(tiao==1)xxx=x,yyy=y;
        }
        else if(fir==3)
        {
            if(pan==1)break;
            if(bian[find2(x,y)][fir]>=1){pan=1;break;}
            nxt=find_qian2(find2(x,y),x);
            ll nxt_x=nxt,nxt_y=x+y-nxt_x;
            //printf("nxt=%lld nxt=%lld
",nxt_x,nxt_y);
            bian[find2(x,y)][fir]++;
            if(bian[find2(x,y)][5-fir]==0)ans+=abs(nxt_x-x);
            //printf("ans=%lld
",ans);
            if(h[make_pair(nxt_x+1,nxt_y)]&&h[make_pair(nxt_x,nxt_y-1)])
            {                
                fir=5-fir;
                x=nxt_x+1;y=nxt_y-1;                  
            }
            else if(h[make_pair(nxt_x+1,nxt_y)])
            {
                fir=1;
                x=nxt_x;y=nxt_y-1;
            }
            else if(h[make_pair(nxt_x,nxt_y-1)])
            {
                fir=4;
                x=nxt_x+1;y=nxt_y;   
            }
            else
            {
                fir=5-fir;
                x=nxt_x+1;y=nxt_y-1;  
            }//printf("gaix=%lld y=%lld
",x,y);/
            if(tiao==1)xxx=x,yyy=y;
        }
        //printf("ans===%lld
",ans);
        if(pan==1)break;
    }
    printf("%lld
",ans);   
    return 0;
}
/*
7 5 3
3 3
4 3
5 3
6 4 SW
*/