Submission #402243

#	Time	Username	Problem	Language	Result	Execution time	Memory
402243		rrrr10000	From Hacks to Snitches (BOI21_watchmen)	C++14	35 / 100	2031 ms	280392 KiB

watchmen

#include <bits/stdc++.h>
#pragma GCC target("avx")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
using namespace std;
#define rep(i, n)  for(long long i=0;i<(long long)(n);i++)
#define REP(i,k,n) for(long long i=k;i<(long long)(n);i++)
#define pb emplace_back
#define lb(v,k) (lower_bound(all(v),(k))-v.begin())
#define ub(v,k) (upper_bound(all(v),(k))-v.begin())
#define fi first
#define se second
#define pi M_PI
#define PQ(T) priority_queue<T>
#define SPQ(T) priority_queue<T,vector<T>,greater<T>>
#define dame(a) {out(a);return 0;}
#define decimal cout<<fixed<<setprecision(15);
#define all(a) a.begin(),a.end()
#define rsort(a) {sort(all(a));reverse(all(a));}
#define dupli(a) {sort(all(a));a.erase(unique(all(a)),a.end());}
typedef long long ll;
typedef pair<ll,ll> P;
typedef tuple<ll,ll,ll> PP;
typedef tuple<ll,ll,ll,ll> PPP;
using vi=vector<ll>;
using vvi=vector<vi>;
using vvvi=vector<vvi>;
using vvvvi=vector<vvvi>;
using vp=vector<P>;
using vvp=vector<vp>;
using vb=vector<bool>;
using vvb=vector<vb>;
const ll inf=1001001001001001001;
const ll INF=1001001001;
const ll mod=998244353;
const double eps=1e-10;
template<class T> bool chmin(T&a,T b){if(a>b){a=b;return true;}return false;}
template<class T> bool chmax(T&a,T b){if(a<b){a=b;return true;}return false;}
template<class T> void out(T a){cout<<a<<'\n';}
template<class T> void outp(T a){cout<<'('<<a.fi<<','<<a.se<<')'<<'\n';}
template<class T> void outvp(T v){rep(i,v.size())cout<<'('<<v[i].fi<<','<<v[i].se<<')';cout<<'\n';}
template<class T> void outvvp(T v){rep(i,v.size())outvp(v[i]);}
template<class T> void outv(T v){rep(i,v.size()){if(i)cout<<' ';cout<<v[i];}cout<<'\n';}
template<class T> void outvv(T v){rep(i,v.size())outv(v[i]);}
template<class T> bool isin(T x,T l,T r){return (l)<=(x)&&(x)<=(r);}
template<class T> void yesno(T b){if(b)out("yes");else out("no");}
template<class T> void YesNo(T b){if(b)out("Yes");else out("No");}
template<class T> void YESNO(T b){if(b)out("YES");else out("NO");}
template<class T> void outset(T s){auto itr=s.begin();while(itr!=s.end()){if(itr!=s.begin())cout<<' ';cout<<*itr;itr++;}cout<<'\n';}
void outs(ll a,ll b){if(a>=inf-100)out(b);else out(a);}
ll gcd(ll a,ll b){if(b==0)return a;return gcd(b,a%b);}
ll modpow(ll a,ll b){ll res=1;a%=mod;while(b){if(b&1)res=res*a%mod;a=a*a%mod;b>>=1;}return res;}
inline ll readll() {
    ll x = 0;
    int neg=1;
    char ch = getchar_unlocked();
    while (ch < '0' || ch > '9'){
        if(ch=='-')neg=-1;
        ch = getchar_unlocked();
    }
    while (ch >= '0' && ch <= '9'){
		x = (x << 3) + (x << 1) + ch - '0';
		ch = getchar_unlocked();
	}
    return x*neg;
}
int main(){
    ll n=readll(),m=readll();
    // map<P,ll> edges;
    vvp g(n);
    rep(i,m){
        ll a=readll()-1,b=readll()-1;
        g[a].pb(b,i);g[b].pb(a,i);
        // edges[P(min(a,b),max(a,b))]=i;
    }
    ll k=readll();
    vi len(n,1),ngv(n,-1),nge(m,-1);
    vvp sp(n);
    rep(j,k){
        ll l=readll();
        vi v(l);
        rep(i,l)v[i]=readll()-1;
        rep(i,l){
            ngv[v[i]]=i;len[v[i]]=l;
            // ll id=edges[P(min(v[i],v[(i+1)%l]),max(v[i],v[(i+1)%l]))];
            // nge[id]=i;
            if(i==l-1&&l==2)break;
            sp[v[i]].pb(v[(i+1)%l],i);
            sp[v[(i+1)%l]].pb(v[i],i);
        }
    }
    rep(i,n)for(auto x:g[i]){
        for(auto&y:sp[i])if(y.fi==x.fi){
            nge[x.se]=y.se;
            y.se=x.se;
        }
    }
    vb ok(n,false);
    rep(i,n)for(auto x:g[i])if(ngv[x.fi]==-1)ok[i]=true;
    vvi dis(n);
    rep(i,n)dis[i]=vi(len[i],inf);
    dis[0][0]=0;
    vi dis2(n,inf);
    queue<P> que,que2;
    que.emplace(0,0);
    ll s=0;
    rep(i,n)s+=dis[i].size();
    while(!que.empty()||!que2.empty()){
        while(que2.size()&&(que.empty()||que2.front().fi==que.front().fi)){
            que.push(que2.front());que2.pop();
        }
        ll i=que.front().fi,j=que.front().se,cost=dis[i][j];que.pop();
        if(chmin(dis2[i],cost)){
            for(auto x:g[i]){
                bool f=true;
                for(auto y:sp[i])if(x==y)f=false;
                if(!f)continue;
                ll nc=cost+1,p=nc%len[x.fi];
                if(ngv[x.fi]==p){
                    nc++;p++;if(p>=len[x.fi])p-=len[x.fi];
                }
                if(chmin(dis[x.fi][p],nc))que.emplace(x.fi,p);
            }
        }
        for(auto x:sp[i]){
            ll p0=cost%len[x.fi],p1=p0+1;if(p1>=len[x.fi])p1-=len[x.fi];
            if(nge[x.se]==p0)continue;
            if(ngv[x.fi]==p1)continue;
            if(chmin(dis[x.fi][p1],cost+1))que.emplace(x.fi,p1);
        }
        ll p1=(cost+1)%len[i],p2=p1+1;if(p2>=len[i])p2-=len[i];
        if(ngv[i]==p1){
            if(ok[i]&&chmin(dis[i][p2],cost+2))que.emplace(i,p2);
        }
        else if(chmin(dis[i][p1],cost+1))que2.emplace(i,p1);
    }
    ll ans=inf;
    for(ll x:dis[n-1])chmin(ans,x);
    if(ans==inf)out("impossible");
    else out(ans);
}

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 0 / 25
• Subtask 6: 0 / 20
• Subtask 7: 0 / 20