Submission #517098

#	Time	Username	Problem	Language	Result	Execution time	Memory
517098		status_coding	Commuter Pass (JOI18_commuter_pass)	C++14	31 / 100	658 ms	29140 KiB

commuter_pass

#include <bits/stdc++.h>

using namespace std;

long long n,m,s,t,a,b,ans;
vector<pair<long long, long long>> v[100005];

long long len[100005][4];
pair<long long, long long> dp[100005];

void djikstra(int s, int nr)
{
    for(int i=1;i<=n;i++)
        len[i][nr] = 1e18;

    multiset<pair<long long, long long>> mul;
    mul.insert({0, s});

    while(!mul.empty())
    {
        long long p = mul.begin()->second;
        long long val = mul.begin()->first;
        mul.erase(mul.begin());

        if(len[p][nr] != 1e18)
            continue;

        len[p][nr] = val;

        for(auto it : v[p])
        {
            if(len[it.first][nr] != 1e18)
                continue;

            mul.insert({val + it.second, it.first});
        }
    }
}

void calcDp(int p)
{
    if(dp[p] != make_pair((long long)1e18, (long long)1e18))
        return;

    dp[p] = {len[p][1], len[p][2]};

    for(auto it : v[p])
        if(len[p][0] - it.second == len[it.first][0])
        {
            calcDp(it.first);

            dp[p].first = min(dp[p].first, dp[it.first].first);
            dp[p].second = min(dp[p].second, dp[it.first].second);
        }

    ans=min(ans, dp[p].first + dp[p].second);
}

int main()
{
    cin>>n>>m>>s>>t>>a>>b;

    for(int i=1;i<=m;i++)
    {
        int x, y, c;
        cin>>x>>y>>c;

        v[x].push_back({y, c});
        v[y].push_back({x, c});
    }

    djikstra(t, 0);
    djikstra(b, 1);
    djikstra(a, 2);

    ans = len[a][1];

    for(int i=1;i<=n;i++)
        dp[i] = {1e18, 1e18};

    calcDp(s);

    cout<<ans;
    return 0;
}

• Subtask 1: 16 / 16
• Subtask 2: 15 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 45