Submission #1129500

#	Time	Username	Problem	Language	Result	Execution time	Memory
1129500		MMihalev	Closing Time (IOI23_closing)	C++17	8 / 100	84 ms	18756 KiB

closing

#include "closing.h"
#include<vector>
#include<iostream>
#include<algorithm>
#include<queue>
#include<set>
#include<tuple>
using namespace std;
const int MAX_N=2e5+5;
const long long INF=(1LL<<60);
int n,x,y;
long long k;
vector<pair<int,int>>g[MAX_N];
long long ans;
bool usedline[MAX_N];
long long bfsdist[MAX_N];
void bfs()
{
    for(int i=0;i<n;i++)bfsdist[i]=INF;
    long long rem=k;
    long long curans=0;

    bfsdist[x]=0;
    bfsdist[y]=0;
    set<pair<long long,int>>q;
    q.insert({0,x});
    q.insert({0,y});

    while(q.size())
    {
        int u,curdist;
        tie(curdist,u)=(*(q.begin()));

        if(rem>=curdist)
        {
            rem-=curdist;
            curans++;
        }
        else break;

        q.erase({curdist,u});

        for(auto [v,edge]:g[u])
        {
            long long len=bfsdist[u]+edge;
            if(len<bfsdist[v])
            {
                q.erase({bfsdist[v],v});
                bfsdist[v]=len;
                q.insert({bfsdist[v],v});
            }
        }
    }

    ans=max(ans,curans);
}
void line()
{
    for(int i=0;i<n;i++)usedline[i]=0;
    usedline[x]=1;
    usedline[y]=1;

    long long distxy=0;

    int u;
    for(int i=0;i<n;i++)
    {
        if(g[i].size()==1)u=i;
    }

    int cntxy=0;
    int prev=-1;
    while(1)
    {
        if(u==x or u==y)
        {
            cntxy++;
        }

        int nu=u;

        for(auto [v,edge]:g[u])
        {
            if(v==prev)continue;

            if(cntxy==1){usedline[v]=1;distxy+=edge;}
            nu=v;
        }

        if(nu==u)break;

        prev=u;
        u=nu;
    }
    ///calculate dist between x and y



    multiset<long long>s;
    long long rem=k;

    cntxy=0;
    prev=-1;
    long long curdist=0;

    while(1)
    {
        if(u==x or u==y)
        {
            cntxy++;
            if(cntxy==1)
            {
                s.insert(distxy);
            }
        }

        int nu=u;

        for(auto [v,edge]:g[u])
        {
            if(v==prev)continue;

            if(cntxy==1)
            {
                curdist+=edge;
                if(curdist<=distxy-curdist)
                {
                    rem-=curdist;
                    s.insert(-curdist+(distxy-curdist));
                }
                else
                {
                    rem-=(distxy-curdist);
                    s.insert(-(distxy-curdist)+curdist);
                }
            }
            nu=v;
        }

        if(nu==u)break;

        prev=u;
        u=nu;
    }

    if(rem>=0)
    {
        long long curans=s.size();

        long long dist;
        dist=0;
        u=x;
        while(g[u].size()>1)
        {
            for(auto [v,edge]:g[u])
            {
                if(usedline[v])continue;
                usedline[v]=1;

                dist+=edge;
                s.insert(dist);
                u=v;
                break;
            }
        }

        dist=0;
        u=y;
        while(g[u].size()>1)
        {
            for(auto [v,edge]:g[u])
            {
                if(usedline[v])continue;
                usedline[v]=1;

                dist+=edge;
                s.insert(dist);
                u=v;
                break;
            }
        }

        while(s.size())
        {
            long long top=(*(s.begin()));
            if(rem>=top)
            {
                rem-=top;
                curans++;
            }
            else break;
            s.erase(s.find(top));
        }

        ans=max(ans,curans);
    }
    ///take at least one from both
}
int max_score(int N, int X, int Y, long long K,std::vector<int> U, std::vector<int> V, std::vector<int> W)
{
    ans=2;
    n=N;
    x=X;
    y=Y;
    k=K;

    int maxdeg=0;

    for(int i=0;i<n;i++)g[i].clear();

    for(int i=0;i<n-1;i++)
    {
        int u,v,w;
        u=U[i];
        v=V[i];
        w=W[i];
        g[u].push_back({v,w});
        g[v].push_back({u,w});
    }

    for(int i=0;i<n;i++)
    {
        maxdeg=max(maxdeg,(int)g[i].size());
    }

    bfs();

    if(maxdeg<=2)line();
    else
    {

    }

    return ans;
}

• Subtask 0: 0 / 0
• Subtask 1: 8 / 8
• Subtask 2: 0 / 9
• Subtask 3: 0 / 12
• Subtask 4: 0 / 14
• Subtask 5: 0 / 9
• Subtask 6: 0 / 11
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 17