Submission #865400

#	Time	Username	Problem	Language	Result	Execution time	Memory
865400		Asamai	Commuter Pass (JOI18_commuter_pass)	C++17	31 / 100	247 ms	20604 KiB

commuter_pass

#include <bits/stdc++.h>

using namespace std;

template<class A, class B> bool maximize(A& x, B y) {if (x < y) return x = y, true; else return false;}
template<class A, class B> bool minimize(A& x, B y) {if (x > y) return x = y, true; else return false;}

#define     all(a)                a.begin(), a.end()
#define     pb                    push_back
#define     pf                    push_front
#define     fi                    first
#define     se                    second
#define     int                   long long

typedef     long long             ll;
typedef     unsigned long long    ull;
typedef     double                db;
typedef     long double           ld;
typedef     pair<db, db>          pdb;
typedef     pair<ld, ld>          pld;
typedef     pair<int, int>        pii;
typedef     pair<ll, ll>          pll;
typedef     pair<ll, int>         plli;
typedef     pair<int, ll>         pill;

const int MAX_N = 1e5 + 5;
const int mod = 1e9 + 7;
const ll inf = 1e18;

int n, m, s, t, x, y;
int go[MAX_N], back[MAX_N];
vector<pii> adj[MAX_N];
priority_queue<pii, vector<pii>, greater<pii>> pq;

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    cin >> n >> m >> s >> t >> x >> y;
    for (int i = 1; i <= m; i++) {
        int U, V, C;
        cin >> U >> V >> C;
        adj[U].pb({V, C});
        adj[V].pb({U, C});
    }

    for (int i = 1; i <= n; i++) {
        go[i] = inf;
    }
    go[s] = 0;
    pq.push({go[s], s});
    while (!pq.empty()) {
        int u = pq.top().se;
        int currW = pq.top().fi;

        pq.pop();

        if (currW > go[u]) {
            continue;
        }

        for (auto it : adj[u]) {
            int v = it.fi;
            int w = it.se;
            if (currW + w < go[v]) {
                go[v] = currW + w;
                pq.push({go[v], v});
            }
        }
    }

    for (int i = 1; i <= n; i++) {
        back[i] = inf;
    }
    back[t] = 0;
    pq.push({back[t], t});
    while (!pq.empty()) {
        int u = pq.top().se;
        int currW = pq.top().fi;

        pq.pop();

        if (currW > back[u]) {
            continue;
        }

        for (auto it : adj[u]) {
            int v = it.fi;
            int w = it.se;
            if (currW + w < back[v]) {
                back[v] = currW + w;
                pq.push({back[v], v});
            }
        }
    }

    for (int u = 1; u <= n; u++) {
        for (auto &it : adj[u]) {
            int v = it.fi;
            int w = it.se;
            if (go[u] + w + back[v] == go[t] || back[u] + w + go[v] == go[t]) {
                it.se = 0;
            }
        }
    }

    for (int i = 1; i <= n; i++) {
        go[i] = inf;
    }
    go[x] = 0;
    pq.push({go[x], x});
    while (!pq.empty()) {
        int u = pq.top().se;
        int currW = pq.top().fi;

        pq.pop();

        if (currW > go[u]) {
            continue;
        }

        for (auto it : adj[u]) {
            int v = it.fi;
            int w = it.se;
            if (currW + w < go[v]) {
                go[v] = currW + w;
                pq.push({go[v], v});
            }
        }
    }

    cout << go[y];

    return 0;
}

/*


Tuesday, 24 October 2023
14:22:00
*/

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