Submission #1082756

#	Time	Username	Problem	Language	Result	Execution time	Memory
1082756		khoile25108	Commuter Pass (JOI18_commuter_pass)	C++14	15 / 100	2068 ms	23288 KiB

commuter_pass

//Created by sangph2612
#include <bits/stdc++.h>
using namespace std;
// #define Sang 1
#define int long long
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define endl '\n'
#define FOR(i, a, b) for(__typeof(b) i = a, _b = b; i <= _b; ++i)
#define FORD(i, a, b) for(__typeof(a) i = a, _b = b; i >= _b; --i)
#define ALL(a) (a).begin(), (a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define MASK(i) (1ll<<(i))
#define BIT(t, i) (((t)>>(i))&1)
typedef vector<int> vi;
typedef pair<int, int> ii;
typedef pair<int, ii> pii;
const int MOD = 1e9+7;
const int N = 1e5+5;
const int INF = 0x3f3f3f3f;

template <class T> bool minimize(T &a, T b) { if (a > b) { a = b; return true; } return false;}

template <class T> bool maximize(T &a, T b) { if (a < b) { a = b; return true; } return false;}

//   ****   ****
//  *     *     *
//  *    K.B    *
//    *       *
//       * *  

int n, m, s, t, u, v, dist[3][N], best[N][2], ans;
// dist[i][0] : khoảng cách ngắn nhất từ s->i
// dist[i][1] : khoảng cách ngắn nhất từ u->i
// dist[i][2] : khoảng cách ngắn nhất từ v->i

vector<ii> G[N];

void dijkstra(int st, int type){
    memset(dist[type], 0x3f, sizeof dist[type]);
    priority_queue<ii, vector<ii>, greater<ii>> Q;
    dist[type][st] = 0;
    Q.push({dist[type][st], st});
    while (!Q.empty()){
        int u = Q.top().se, w = Q.top().fi; Q.pop();
        if (w != dist[type][u]) continue;
        for (auto v : G[u]){
            if (minimize(dist[type][v.fi], dist[type][u] + v.se)){
                Q.push({dist[type][v.fi], v.fi});
            }
        }
    }
}

void dfs(int u){
    best[u][0] = dist[1][u];
    best[u][1] = dist[2][u];
    // cerr << u << endl;
    for (auto v : G[u]){
        if (dist[0][v.fi] + v.se != dist[0][u]) continue;
        dfs(v.fi);
        minimize(best[u][0], best[v.fi][0]);
        minimize(best[u][1], best[v.fi][1]);
    }
    minimize(ans, dist[1][u] + best[u][1]);
    minimize(ans, dist[2][u] + best[u][0]);
}

int32_t main() {
   ios_base::sync_with_stdio(false);
   cin.tie(0); cout.tie(0);
    cin >> n >> m >> s >> t >> u >> v;
    FOR (i, 1, m){
        int u, v, c; cin >> u >> v >> c;
        G[u].pb({v,c});
        G[v].pb({u,c});
    }
    dijkstra(s, 0);
    dijkstra(u, 1);
    dijkstra(v, 2);
    ans = dist[1][v];
    dfs(t);
    // cout << dist[1][5] << ' ' << dist[2][2] << endl;
    cout << ans;

    return 0;
}

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