Submission #941626

#	Time	Username	Problem	Language	Result	Execution time	Memory
941626		May27_th	Commuter Pass (JOI18_commuter_pass)	C++17	31 / 100	286 ms	33724 KiB

commuter_pass

#include<bits/stdc++.h>
#define taskname "A"
using namespace std;

void World_Final();
void Solve();

int main(){
    ios_base::sync_with_stdio(false); cin.tie(nullptr);
    if (fopen(taskname".in", "r")) {
        freopen(taskname".in", "r", stdin);
        freopen(taskname".out", "w", stdout);
    }
    World_Final();
}

void World_Final(){
    int Tests = 1;
    //cin >> Tests;
    for (int i = 1; i <= Tests; i ++) {
        //cout << i << "\n";
        Solve();
    }
}

const int MOD = 1e9 + 7;
const int MAXN = 2e5 + 10;
const int64_t INF = 1e18;
int N, M, S, T, U, V; vector<pair<int, int>> G[MAXN]; int64_t D[MAXN][2], F[MAXN][3];
pair<int64_t, int> Trace[MAXN];
void Dijkstra(int START, int t){
    for (int i = 1; i <= N; i ++) D[i][t] = INF; D[START][t] = 0;
    priority_queue<pair<int64_t, int>> pq; pq.push(make_pair(0, START));
    while (!pq.empty()) {
        int64_t d; int u; tie(d, u) = pq.top(); pq.pop();
        if (-d != D[u][t]) continue;
        for (auto [v, w] : G[u]) {
            if (D[v][t] > D[u][t] + w) {
                D[v][t] = D[u][t] + w;
                pq.push(make_pair(-D[v][t], v));
            }
        }
    }
}
void Solve(){
    cin >> N >> M >> S >> T >> U >> V;
    for (int i = 1; i <= M; i ++) {
        int u, v, w; cin >> u >> v >> w;
        G[u].push_back(make_pair(v, w));
        G[v].push_back(make_pair(u, w));
    } Dijkstra(S, 0); Dijkstra(T, 1);
    memset(F, 0x3f3f, sizeof(F));
    F[U][0] = 0;
    priority_queue<pair<int64_t, pair<int, int>>> pq; pq.push(make_pair(0, make_pair(U, 0)));
    while (!pq.empty()) {
        int64_t d = pq.top().first;
        int u, t; tie(u, t) = pq.top().second;
        pq.pop();
        if (-d != F[u][t]) continue;
        for (auto [v, w] : G[u]) {
            if (t == 0) {
                if (F[v][0] > F[u][0] + w) {
                    F[v][0] = F[u][0] + w;
                    pq.push(make_pair(-F[v][t], make_pair(v, t)));
                } if (F[v][1] > F[u][0]) {
                    int64_t tot = Trace[u].first + w;
                    int64_t minDist = min(D[u][0] + tot + D[v][1], D[u][1] + tot + D[v][0]);
                    if (minDist == D[T][0]) {
                        F[v][1] = F[u][0];
                        Trace[v] = make_pair(tot, u);
                        //cout << u << " " << v << " " << F[v][1] << " " << F[u][0] << "\n";
                        //cout << u << " " << v << " " << w << "\n";
                        pq.push(make_pair(-F[v][1], make_pair(v, 1)));
                    }
                }
            } else if (t == 1) {
                if (F[v][1] > F[u][1]) {
                    int64_t tot = Trace[u].first + w;
                    int st = Trace[u].second;
                    int64_t minDist = min(D[st][0] + tot + D[v][1], D[st][1] + tot + D[v][0]);
                    if (minDist == D[T][0]) {
                        F[v][1] = F[u][1];
                        Trace[v] = make_pair(tot, st);
                        //cout << u << " " << v << " " << w << "\n";
                        pq.push(make_pair(-F[v][1], make_pair(v, 1)));
                    }
                } if (F[v][2] > F[u][1] + w) {
                    F[v][2] = F[u][1] + w;
                    pq.push(make_pair(-F[v][2], make_pair(v, 2)));
                }
            } else if (t == 2) {
                if (F[v][2] > F[u][2] + w) {
                    F[v][2] = F[u][2] + w;
                    pq.push(make_pair(-F[v][2], make_pair(v, 2)));
                }
            }
        }
    }
    //cout << F[V][0] << " " << F[V][1] << " " << F[V][2] << "\n";
    cout << min({F[V][0], F[V][1], F[V][2]});
}

Compilation message (stderr)

commuter_pass.cpp: In function 'void Dijkstra(int, int)':
commuter_pass.cpp:32:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
   32 |     for (int i = 1; i <= N; i ++) D[i][t] = INF; D[START][t] = 0;
      |     ^~~
commuter_pass.cpp:32:50: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   32 |     for (int i = 1; i <= N; i ++) D[i][t] = INF; D[START][t] = 0;
      |                                                  ^
commuter_pass.cpp: In function 'int main()':
commuter_pass.cpp:11:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 |         freopen(taskname".in", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
commuter_pass.cpp:12:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   12 |         freopen(taskname".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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