HDU3900 状压BFS

来源：互联网发布：泰迪网络用语编辑：程序博客网时间：2024/06/15 05:43
#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;}
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