HDU 3900 状压BFS

#include <cstdio>
#include <iostream>
#include <algorithm>
#include <queue>
#include <set>
#include <cmath>
#define LL long long
#define print(k) cout<<#k"="<<k<<endl;
using namespace std;
struct State
{
LL state,step;
};

struct Block
{
LL l,c;
bool t;
}block[20];
LL n,red;

inline LL getr(LL x,LL k)
{
return (x&(7LL<<k*3))>>k*3;
}

inline bool check(LL x,LL k1,LL k2)
{
if(getr(x,k1)>=getr(x,k2)) swap(k1,k2);
if(block[k1].t==block[k2].t)
{
if(block[k1].c!=block[k2].c) return true;
if(getr(x,k1)+block[k1].l>getr(x,k2)) return false;
else return true;
}
if(getr(x,k1)<=block[k2].c && getr(x,k1)+block[k1].l>block[k2].c &&
getr(x,k2)<=block[k1].c && getr(x,k2)+block[k2].l>block[k1].c) return false;
else return true;
}

inline bool check(LL x)
{
LL i,j;
for(i=0;i<n;i++)
{
if(getr(x,i)+block[i].l>6)
{
return false;
}
for(j=0;j<i;j++)
{
if(!check(x,i,j))
{
return false;
}
}
}
return true;
}

inline bool done(LL x)
{
if(getr(x,red)+block[red].l==6) return true;
return false;
}

int main()
{
//freopen("in.txt","r",stdin);
ios::sync_with_stdio(false);
while(cin>>n)
{
LL i,j,k;
LL lx,ly,rx,ry;
State head,tail;
tail.state=0;
for(i=0;i<n;i++)
{
cin>>k>>lx>>ly>>rx>>ry;
if(lx==rx)
{
block[i].t=0;
block[i].l=abs(ly-ry)+1;
block[i].c=lx;
tail.state+=min(ly,ry)<<3*k;
}
else if(ly==ry)
{
block[i].t=1;
block[i].l=abs(lx-rx)+1;
block[i].c=ly;
tail.state+=min(lx,rx)<<3*k;
}
else exit(-1);
}
cin>>red;
set<LL> st;st.clear();
st.insert(tail.state);
queue<State> q;
tail.step=0;
q.push(tail);
LL ans=-1;
while(q.size() && ans<0)
{
head=q.front();
///if(getr(head.state,red)==0) print(getr(head.state,red));
if(done(head.state))
{
ans=head.step;
break;
}
for(i=0;i<n && ans<0;i++)
{
LL m=getr(head.state,i);
for(k=1;k+m+block[i].l<=6 && ans<0 && check(head.state+k*(1LL<<3*i));k++) if(st.count(head.state+k*(1LL<<3*i))==0)
{
//print(m) print(k)
tail.state=head.state+k*(1LL<<3*i);
tail.step=head.step+1;
q.push(tail);
st.insert(tail.state);
if(done(tail.state))
{
ans=tail.step;
break;
}
}
for(k=1;m-k>=0 && ans<0 && check(head.state-k*(1LL<<3*i));k++) if(st.count(head.state-k*(1LL<<3*i))==0)
{
tail.state=head.state-k*(1LL<<3*i);
tail.step=head.step+1;
q.push(tail);
st.insert(tail.state);
if(done(tail.state))
{
ans=tail.step;
break;
}
}
}
q.pop();
}
cout<<max(ans,1LL)<<endl;
}
return 0;
}