Submission #1181182

#	Time	Username	Problem	Language	Result	Execution time	Memory
1181182		Szymon_Pilipczuk	Olympic Bus (JOI20_ho_t4)	C++20	37 / 100	1096 ms	15164 KiB

ho_t4

#pragma GCC optimize("O3")
#include <bits/stdc++.h>
using namespace std;
#define ll long long
int n,m;
long long k[50000][4];
long long inf = (long long)1000000000*1000000000;
long long dis[4][200];
vector<long long> dis3[4][200];
map<vector<long long>,int> kr;
vector<vector<vector<long long>>> gr[2];
priority_queue<vector<long long>> pq;
void dk(long long v,long long c,long long p)
{
    for(vector<ll> &i : gr[p%2][v])
    {
        if(dis[p][i[0]] > c+i[1])
        {
            pq.push({-1*(c+i[1]),i[0],p});
            dis[p][i[0]] = i[1]+c;
            if(p%2 == 0)
            {
                dis3[p][i[0]] = {v,i[0],i[1],i[2]};
            }
            else
            {
                dis3[p][i[0]] = {i[0],v,i[1],i[2]};
            }

        }
    }
}
priority_queue<vector<long long>> pq2;
long long dis2[200];
void dk2(long long c,long long v)
{
    for(vector<ll> &i : gr[0][v])
    {
        if(dis2[i[0]] > c+i[1])
        {
            pq2.push({-1*(c+i[1]),i[0]});
            dis2[i[0]] = c+i[1];
        }
    }
}
void del()
{
    for(int i = 0;i<n;i++)
    {
        dis2[i] = inf;
    }
}
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin>>n>>m;
    gr[0].resize(n);
    gr[1].resize(n);
    for(int i = 0;i<4;i++)
    {
        for(int j = 0;j<n;j++)
        {
            dis[i][j] = inf;
        }
    }
    for(int i = 0;i<m;i++)
    {
        long long u,v,c,d;
        cin>>u>>v>>c>>d;
        u--;v--;
        kr[{u,v,c,d}] = i;
        gr[0][u].push_back({v,c,d});
        gr[1][v].push_back({u,c,d});
        k[i][0] = u;
        k[i][1] = v;
        k[i][2] = c;
        k[i][3] = d;
    }
    pq.push({0,0,0});
    pq.push({0,0,1});
    pq.push({0,n-1,2});
    pq.push({0,n-1,3});
    dis[0][0]= 0;
    dis[1][0] = 0;
    dis[2][n-1] = 0;
    dis[3][n-1] = 0;
    while(!pq.empty())
    {
        long long a,b,c;
        a = pq.top()[1];
        b = pq.top()[0]*-1;
        c = pq.top()[2];
        pq.pop();
        if(dis[c][a] == b)
        {
            dk(a,b,c);
        }


    }
    unordered_set<long long> sps;
    for(int i = 0;i<2;i++)
    {
        for(int j = 1;j<n;j++)
        {
            if(dis3[i][j].size() != 0)
            {
                sps.insert(kr[dis3[i][j]]);
            }
        }
    }
    for(int i = 2;i<4;i++)
    {
        for(int j = 0;j<n-1;j++)
        {
            if(dis3[i][j].size() != 0)
            {
                sps.insert(kr[dis3[i][j]]);
            }
        }
    }
    long long ans = dis[0][n-1]+dis[2][0];
    dis[2][n-1] = 0;
    dis[3][n-1] = 0;
    dis[0][0] = 0;
    dis[1][0] = 0;
    for(int i = 0;i<m;i++)
    {
        if(sps.find(i) == sps.end())
        {
            ans = min(ans,k[i][3]+min(dis[0][n-1],dis[0][k[i][1]]+k[i][2]+dis[3][k[i][0]])+min(dis[2][0],dis[2][k[i][1]]+k[i][2]+dis[1][k[i][0]]));
        }
    }
    del();
    for(int i = 0;i<n;i++)
    {
        for(int j = 0;j<gr[0][i].size();j++)
        {
            if(sps.find(kr[{i,gr[0][i][j][0],gr[0][i][j][1],gr[0][i][j][2]}]) != sps.end())
            {

                long long cu = gr[0][i][j][0];
                long long cans = gr[0][i][j][2];
                gr[0][i][j][0] = i;
                gr[0][cu].push_back({i,gr[0][i][j][1]});
                pq2.push({0,0});
                dis2[0] = 0;
                while(!pq2.empty())
                {
                    long long a = pq2.top()[0]*-1,b = pq2.top()[1];
                    pq2.pop();
                    if(dis2[b] == a)
                    {
                        dk2(a,b);
                    }
                }
                cans += dis2[n-1];
                del();
                pq2.push({0,n-1});
                dis2[n-1] =0 ;
                while(!pq2.empty())
                {
                    long long a = pq2.top()[0]*-1,b = pq2.top()[1];
                    pq2.pop();
                    if(dis2[b]== a)
                    {
                        dk2(a,b);
                    }

                }
                cans+=dis2[0];
                del();
                gr[0][i][j][0] = cu;
                gr[0][cu].pop_back();
                ans = min(ans,cans);
            }
        }
    }
    long long cans = 0;
    pq2.push({0,0});
    dis2[0] = 0;
    while(!pq2.empty())
    {
        long long a = pq2.top()[0]*-1,b = pq2.top()[1];
        pq2.pop();
        if(dis2[b] == a)
        {
            dk2(a,b);
        }
    }
    cans += dis2[n-1];
    del();
    pq2.push({0,n-1});
    dis2[n-1] = 0;
    while(!pq2.empty())
    {
        long long a = pq2.top()[0]*-1,b = pq2.top()[1];
        pq2.pop();
        if(dis2[b] == a)
        {
            dk2(a,b);
        }
    }
    cans+=dis2[0];
    del();
    ans = min(ans,cans);
    if(ans >= inf)
    {
        cout<<-1<<"\n";
    }
    else
    {
        cout<<ans<<"\n";
    }
}

• Subtask 1: 5 / 5
• Subtask 2: 11 / 11
• Subtask 3: 21 / 21
• Subtask 4: 0 / 63