Submission #1283544

#	Time	Username	Problem	Language	Result	Execution time	Memory
1283544		nemkho	Commuter Pass (JOI18_commuter_pass)	C++17	0 / 100	2105 ms	327680 KiB

commuter_pass

#include <bits/stdc++.h>
#define ll long long
#define pr pair <ll, int>
#define fi first
#define se second
using namespace std;
const int N = 1e5 + 5;
struct haha
{
    ll val;
    int ver, type, g;
};
struct cmp
{
    bool operator() (haha &a, haha &b)
    {
        return a.val > b.val;
    }
};
int n, m, s, t, U, V;
vector <pr> a[N], g_s[N], g_t[N];
ll dist[N][5], d_s[N], d_t[N];

void inp()
{
    cin >> n >> m >> s >> t >> U >> V;
    for (int i = 1; i <= m; i++)
    {
        int x, y;
        ll w;
        cin >> x >> y >> w;
        a[x].push_back({w, y});
        a[y].push_back({w, x});
    }
}

void dijkstra_ST()
{
    priority_queue<pr, vector<pr>, greater<pr>> q;
    q.push({0, s});
    memset(d_s, 0x3f, sizeof(d_s));
    d_s[s] = 0;
    while (!q.empty())
    {
        int u = q.top().se;
        ll k = q.top().fi;
        q.pop();
        if (k > d_s[u])
            continue;
        for (pr i : a[u])
        {
            int v = i.se;
            ll val = k + i.fi;
            if (d_s[v] > val)
            {
                d_s[v] = val;
                q.push({val, v});
            }
        }
    }
}

void dijkstra_TS()
{
    priority_queue<pr, vector<pr>, greater<pr>> q;
    q.push({0, t});
    memset(d_t, 0x3f, sizeof(d_t));
    d_t[t] = 0;
    while (!q.empty())
    {
        int u = q.top().se;
        ll k = q.top().fi;
        q.pop();
        if (k > d_t[u])
            continue;
        for (pr i : a[u])
        {
            int v = i.se;
            ll val = k + i.fi;
            if (d_t[v] > val)
            {
                d_t[v] = val;
                q.push({val, v});
            }
        }
    }
}

void dijkstra_UV ()
{
    priority_queue <haha, vector<haha>, cmp> q;
    memset(dist, 0x3f, sizeof(dist));
    dist[U][0] = dist[U][1] = dist[U][2] = 0;
    if (d_s[t] == d_s[U] + d_t[U])
    {
        q.push({0, U, 1, 2});
        q.push({0, U, 1, 1});
    }
    else
        q.push({0, U, 0, 0});
    while (!q.empty())
    {
        int u = q.top().ver, type = q.top().type, g = q.top().g;
        ll k = q.top().val;
        //cout << u << " " << type << " " << g << " " << k << "\n";
        q.pop();
        if (k > dist[u][type])
            continue;
        vector <pr> tmp;
        if (g == 1)
            tmp = g_t[u];
        else if (g == 2)
            tmp = g_s[u];
        else
            tmp = a[u];
        for (pr i : tmp)
        {
            ll val = k + i.fi;
            int v = i.se;

            if (type == 0)
            {
                int graph = 0;
                if (d_s[t] == d_s[v] + d_t[v])
                    graph = 2;
               // cout << u << " " << v << " " << graph << "\n";
                if (graph && dist[v][1] > val)
                {
                    q.push({val, v, 1, 1});
                    q.push({val, v, 1, 2});
                    dist[v][1] = val;
                }
                if (dist[v][0] > val)
                {
                    q.push({val, v, 0, 0});
                    dist[v][0] = val;
                }
            }

            if(type == 1)
            {
                if (dist[v][1] > dist[u][1])
                {
                    q.push({dist[u][1], v, 1, g});
                    dist[v][1] = dist[u][1];
                }
            }

            if (type == 2)
            {
                if (dist[v][2] > val)
                {
                    dist[v][2] = val;
                    q.push({val, v, 2, 0});
                }
            }
        }
        if (type == 1)
        {
            for (pr i : a[u])
            {
                int v = i.se;
                ll val = i.fi + k;
                if (dist[v][2] > val)
                {
                    q.push({val, v, 2, 0});
                    dist[v][2] = val;
                }
            }
        }
    }
}

void trace(int u, ll d[], int pre, int type)
{
    for (pr i : a[u])
    {
        int v = i.se;
        if (d[u] == d[v] + i.fi && v != pre && d_s[t] == d_s[v] + d_t[v])
        {
            if (type == 1)
                g_s[v].push_back({i.fi, u});
            else
                g_t[v].push_back({i.fi, u});
            trace(v, d, u, type);
        }
    }
}

void solve()
{
    dijkstra_ST();
    dijkstra_TS();
    trace(t, d_s, -1, 1);
    trace(s, d_t, -1, 2);
//    for (int i = 1; i <= n; i++)
//    {
//        cout << i << " ";
//        for (pr j : g_t[i])
//            cout << j.se << " ";
//        cout << "\n";
//    }
    dijkstra_UV();
    cout << min({dist[V][1], dist[V][2], dist[V][0]});
}
int main()
{
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    inp();
    solve();
}

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