Submission #915771

#	Time	Username	Problem	Language	Result	Execution time	Memory
915771		AndrijaM	Valley (BOI19_valley)	C++14	59 / 100	467 ms	42624 KiB

valley

#include <bits/stdc++.h>
using namespace std;

const long long maxn=1e5+10;
const long long logn=25;
const long long mod=1e9+7;

long long n,s,q,e;
vector<pair<long long,long long>>g[maxn];
set<long long>ins;
vector<pair<long long,long long>>pr;
long long up_node[maxn][logn];
long long dep[maxn];

struct N
{
    long long idx;
    long long dis;
    N(){}
    N(long long _idx,long long _dis)
    {
        idx=_idx;
        dis=_dis;
    }
    bool operator <(const N &tmp)const
    {
        return dis>tmp.dis;
    }
};

void dfs(long long node,int par)
{
    up_node[node][0]=par;
    dep[node]=dep[up_node[node][0]]+1;
    for(long long i=1;i<logn;i++)
    {
        up_node[node][i]=up_node[up_node[node][i-1]][i-1];
    }
    for(auto ax:g[node])
    {
        if(ax.first!=par)
        dfs(ax.first,node);
    }
}

long long UP(long long node,long long k)
{
    for(long long i=0;i<logn;i++)
    {
        if(k&(1<<i))
        {
            node=up_node[node][i];
        }
    }
    return node;
}

long long LCA(long long a,long long b)
{
    if(dep[a]<dep[b])
    {
        swap(a,b);
    }
    long long k=dep[a]-dep[b];
    a=UP(a,k);
    if(a==b)
    {
        return a;
    }
    for(long long i=logn-1;i>=0;i--)
    {
        if(up_node[a][i]!=up_node[b][i])
        {
            a=up_node[a][i];
            b=up_node[b][i];
        }
    }
    return up_node[a][0];
}


int main()
{
    cin>>n>>s>>q>>e;
    memset(dep,0,sizeof dep);
    memset(up_node,0,sizeof up_node);
    for(long long i=0;i<n-1;i++)
    {
        long long a,b,c;
        cin>>a>>b>>c;
        g[a].push_back({b,c});
        g[b].push_back({a,c});
        pr.push_back({a,b});
    }
    dfs(1,0);
    for(long long i=0;i<s;i++)
    {
        long long pom;
        cin>>pom;
        ins.insert(pom);
    }
    while(q--)
    {
        long long idxe,st;
        cin>>idxe>>st;
        idxe--;
        long long n1=pr[idxe].first;
        long long n2=pr[idxe].second;
        ///cout<<n1<<" "<<n2<<endl;
        if(n<1100)
        {
            ///kolku e odalecen od S
            priority_queue<N>Q;
            Q.push(N(st,0));
            long long d[n+10];
            for(long long pi=0;pi<n+10;pi++)
            {
                d[pi]=1e18;
            }
            d[st]=0;
            bool ok=false;
            while(!Q.empty())
            {
                N teme=Q.top();Q.pop();
                if(teme.idx==e)
                {
                    cout<<"escaped"<<endl;
                    ok=true;
                    break;
                }
                for(auto ax:g[teme.idx])
                {
                    if((teme.idx==n1 && ax.first==n2) || (teme.idx==n2 && ax.first==n1))
                    {
                        continue;
                    }
                    if(teme.dis+ax.second<d[ax.first])
                    {
                        d[ax.first]=teme.dis+ax.second;
                        Q.push(N(ax.first,d[ax.first]));
                    }
                }
            }
            long long ans=1e18;
            for(auto pom:ins)
            {
                ans=min(ans, d[pom]);
            }
            if(!ok)
            {
                if(ans!=1e18)
                cout<<ans<<endl;
                else
                {
                    cout<<"oo"<<endl;
                }
            }
        }
        else
        {
            bool ok=false;
            if(LCA(n1,n2)==n1)
            {
                if((LCA(n2,e)==n2 && LCA(n2,st)==n2) || (LCA(n2,e)!=n2 && LCA(n2,st)!=n2))
                {
                    ok=true;
                    cout<<"escaped"<<endl;
                }
            }
            else
            {
                if((LCA(n1,e)==n1 && LCA(n1,st)==n1) || (LCA(n1,e)!=n1 && LCA(n1,st)!=n1))
                {
                    ok=true;
                    cout<<"escaped"<<endl;
                }
            }
            if(!ok)
            {
                cout<<0<<endl;
            }
        }
    }
	return 0;
}

• Subtask 1: 9 / 9
• Subtask 2: 27 / 27
• Subtask 3: 23 / 23
• Subtask 4: 0 / 41