Submission #905059

#	Time	Username	Problem	Language	Result	Execution time	Memory
905059		HorizonWest	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	348 ms	28120 KiB

commuter_pass

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

#define endl '\n'
#define db double
#define ll __int128
#define int long long
#define pb push_back
#define fs first
#define sd second
#define Mod long(1e9 + 7)
#define all(x) x.begin(), x.end()
#define unvisited long(-1)
#define Eps double(1e-9)
#define _for(i, n) for(int i = 0; i < (n); i++)
#define dbg(x) cout << #x ": " << x << endl;

const int Max = 1e6 + 7, Inf = 1e16 + 7;

void print(bool x) { cout << (x ? "YES" : "NO") << endl; }

string tostring (__int128 x)
{
    string ans = "";
    while(x > 0)
    {
        ans += (x % 10 + '0');
        x /= 10;
    }
    reverse(all(ans));
    return ans;
}

vector <vector<pair<int, int>>> v; 

vector <int> Dijkstra(int n, int x)
{
    vector <int> dist(n+1, Inf), pass(n+1, 0);

    priority_queue <pair<int, int>> pq; 
    dist[x] = 0; pq.push({ 0, x });

    while (!pq.empty())
    {
        int x = pq.top().sd; pq.pop(); 

        if(pass[x]) continue;
        pass[x] = 1; 

        for(auto& u : v[x]) 
        {
            int node = u.fs, w = u.sd; 
            if(dist[x] + w < dist[node])
            {
                dist[node] = dist[x] + w; 
                pq.push({ -dist[node], node }); 
            }
        }
    }
    return dist;
}

void solve()
{
    int N, M, S, T, U, V; cin >> N >> M >> S >> T >> U >> V; 
    v.assign(N + 1, vector <pair<int, int>> ()); 

    for(int i = 0; i < M; i++)
    {
        int a, b, c; cin >> a >> b >> c;
        v[a].push_back({ b, c }); 
        v[b].push_back({ a, c });  
    } 
    vector <vector<int>> dist(3, vector <int> ()), 
                dp(N + 1, vector <int> (2, 0));

    dist[0] = Dijkstra(N, S); 
    dist[1] = Dijkstra(N, U); 
    dist[2] = Dijkstra(N, V); 

    priority_queue <pair<int, int>> pq; 
    int ans = dist[1][V]; pq.push({ 0, T }); 

    for(int i = 1; i <= N; i++)
    {
        dp[i][0] = dist[1][i]; 
        dp[i][1] = dist[2][i]; 
    }
    vector <int> pass(N + 1, 0); 
    while(!pq.empty())
    {
        int x = pq.top().sd; pq.pop();
        if(pass[x]) continue;
        pass[x] = 1; 
        ans = min(ans, min(dp[x][0] + dist[2][x], dp[x][1] + dist[1][x])); 

        for(auto& u : v[x]) 
        {
            if(dist[0][u.fs] + u.sd == dist[0][x])
            {
                dp[u.fs][0] = min(dp[u.fs][0], dp[x][0]);
                dp[u.fs][1] = min(dp[u.fs][1], dp[x][1]);
                pq.push({ dist[0][u.fs], u.fs }); 
            }
        }
    }

    cout << ans << endl; 
}

int32_t main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int Q = 1; //cin >> Q;

    while (Q--)
    {
        solve();
    }

    return 0;
}

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