Submission #853970

#	Time	Username	Problem	Language	Result	Execution time	Memory
853970		trytovoi	Commuter Pass (JOI18_commuter_pass)	C++14	40 / 100	146 ms	15084 KiB

commuter_pass

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

template<typename T> bool ckmin(T& x, const T& y) { return x > y ? x = y, 1 : 0; }
template<typename T> bool ckmax(T& x, const T& y) { return x < y ? x = y, 1 : 0; }

const long long INF = (long long) 1e18;
const int MAX_NODE = (int) 1e5 + 5;
const int MAX_EDGE = (int) 2e5 + 5;

int n, m;
int S, T, U, V;
vector<pair<int, int>> adj[MAX_NODE];

struct Data {
    int u;
    long long w;
    
    Data(int _u = 0, long long _w = 0) {
        u = _u; w = _w;
    }
    
    bool operator < (const Data& other) const {
        return w > other.w;
    }
};

namespace SUBTASK_1 {
    
    void dijkstra(int s, vector<long long>& dist) {
        priority_queue<Data> Q;
        Q.push(Data(s, dist[s] = 0));
        while (!Q.empty()) {
            auto [u, du] = Q.top(); Q.pop();
            if (du != dist[u]) continue;
            
            for (auto [v, dv] : adj[u]) {
                long long cost = du + dv;
                if (ckmin(dist[v], cost)) Q.push(Data(v, dist[v]));
            }
        }
    }
    
    void solve(void) {
        vector<long long> distSU(n + 1, INF);
        dijkstra(S, distSU);
        vector<long long> distT(n + 1, INF);
        dijkstra(T, distT);
        vector<long long> distV(n + 1, INF);
        dijkstra(V, distV);
        
        long long ans = distV[U];
        for (int i = 1; i <= n; ++i) if (distSU[i] + distT[i] == distSU[T]) ckmin(ans, distV[i]);
        cout << ans << '\n';
    }
    
}

namespace SUBTASK_3 {
    
    const int MX = 303;
    
    long long dist[MX][MX];
    
    void solve(void) {
        memset(dist, 0x3f, sizeof dist);
        for (int i = 1; i <= n; ++i) {
            dist[i][i] = 0;
            for (auto [v, w] : adj[i]) dist[i][v] = dist[v][i] = w;
        }
        
        for (int k = 1; k <= n; ++k) for (int i = 1; i <= n; ++i) for (int j = 1; j <= n; ++j)
            ckmin(dist[i][j], dist[i][k] + dist[k][j]);
        
        long long ans = dist[U][V];
        for (int i = 1; i <= n; ++i) for (int j = 1; j <= n; ++j) 
            if (dist[S][i] + dist[i][j] + dist[j][T] == dist[S][T]) ckmin(ans, min(dist[V][i] + dist[j][U], dist[U][i] + dist[j][V]));
        cout << ans << '\n';
    }
    
}

int main(void) {
    ios::sync_with_stdio(false); cin.tie(0);
    cin >> n >> m >> S >> T >> U >> V;
    for (int i = 1; i <= m; ++i) {
        int u, v, w; cin >> u >> v >> w;
        adj[u].push_back(make_pair(v, w));
        adj[v].push_back(make_pair(u, w));
    }
    if (S == U) {
        SUBTASK_1::solve();
        return 0;
    }
    if (n <= 300) {
        SUBTASK_3::solve();
        return 0;
    }
    return 0;
}

Compilation message (stderr)

commuter_pass.cpp: In function 'void SUBTASK_1::dijkstra(int, std::vector<long long int>&)':
commuter_pass.cpp:34:18: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   34 |             auto [u, du] = Q.top(); Q.pop();
      |                  ^
commuter_pass.cpp:37:23: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   37 |             for (auto [v, dv] : adj[u]) {
      |                       ^
commuter_pass.cpp: In function 'void SUBTASK_3::solve()':
commuter_pass.cpp:69:23: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   69 |             for (auto [v, w] : adj[i]) dist[i][v] = dist[v][i] = w;
      |                       ^

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