제출 #159901

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
159901		XCoder	Commuter Pass (JOI18_commuter_pass)	C++14	0 / 100	742 ms	18456 KiB

commuter_pass

#include <bits/stdc++.h>

#define FOR(i,s,e) for(int i=(s);i<(int)(e);i++)
#define FOE(i,s,e) for(int i=(s);i<=(int)(e);i++)
#define REP(i,n)   FOR(i,0,n)
#define ALL(x) (x).begin(), (x).end()
#define CLR(s) memset(s,0,sizeof(s))
#define PB push_back
#define ITER(v) __typeof((v).begin())
#define FOREACH(i,v) for(ITER(v) i=(v).begin();i!=(v).end();i++)

#define x first
#define y second

using namespace std;

typedef long long LL;
typedef pair<int,int> pii;
typedef pair<LL, LL> pll;
typedef map<int,int> mii;
typedef vector<int> vi;

const LL INF = 1LL << 40;
using Graph = vector<vector<pii>>;
using Dist = vector<LL>;
using Node = tuple<LL, int>;  // <cost, node_id>

int N, M, S, T, U, V;
Graph G;

Dist compute_shortest_path(Graph &G, vector<int> src_nodes, int N) {
    Dist D(N + 1, INF);
    priority_queue<Node, vector<Node>, greater<Node>> pq;

    for (auto &src : src_nodes) {
        D[src] = 0LL;
        pq.push({D[src], src});
    }

    while (!pq.empty()) {
        LL cur;
        int x;
        tie(cur, x) = pq.top();
        pq.pop();

        if (D[x] > cur) continue;

        for (auto &it : G[x]) {
            LL cost;
            int y;
            tie(y, cost) = it;
            if (cur + cost < D[y]) {
                D[y] = cur + cost;    
                pq.push({D[y], y});
            }
        }
    }
    return D;
}


int main() {
    int A, B, C;
    cin >> N >> M >> S >> T >> U >> V;

    G.resize(N + 1);
    FOR(_, 0, M) {
        cin >> A >> B >> C;
        G[A].PB({B, C});
        G[B].PB({A, C});
    }

    Dist src_dist = compute_shortest_path(G, {S}, N);
    Dist dst_dist = compute_shortest_path(G, {T}, N);
    //cout << src_dist[T] << " " << dst_dist[S] << endl;

    // Case 1: Travel U -> V via stations in the railway pass
    LL shortest_path_cost = src_dist[T];
    assert (src_dist[T] == dst_dist[S]);
    vector<int> shortest_path_nodes;
    FOE(x, 1, N)
        if (src_dist[x] + dst_dist[x] == shortest_path_cost)
            shortest_path_nodes.PB(x);
    Dist pass_dist = compute_shortest_path(G, shortest_path_nodes, N);

    // Case 2: Travel U -> V via direct shortest path
    // WA #1
    Dist direct_dist = compute_shortest_path(G, {U}, N);

    //cout << pass_dist[U] + pass_dist[V] << endl;
    //cout << direct_dist[V] << endl;

    LL ans = min(
        pass_dist[U] + pass_dist[V],  // Case #1
        direct_dist[V] // Case #2
    );
    cout << ans << endl;

    return 0;
}

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