Submission #1277888

#	Time	Username	Problem	Language	Result	Execution time	Memory
1277888		phuocrucpp	Commuter Pass (JOI18_commuter_pass)	C++20	100 / 100	288 ms	31580 KiB

commuter_pass

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#include<bits/stdc++.h>
#define task "main"
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
#define endl '\n'
#define int long long
#define pb push_back
#define fi first
#define se second
#define ii pair<int,int>
#define iii pair<int,ii>
#define iv pair<ii, ii>
#define base 341
#define MASK(i) (1ll << i)
#define oo 1e18
#define isOn(x,i) ((x) & MASK(i))
#define bitOn(x,i) ((x) | MASK(i))
#define bitOff(x,i) ((x) & ~MASK(i))
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define __lcm(a,b) (1ll * ((a) / __gcd((a), (b))) * (b))
using namespace std;
//using namespace __gnu_pbds;
const int maxn = 1e6 + 5;
int n, m, s, t, u, v, dists[maxn], distt[maxn], distu[maxn], distv[maxn];
vector <ii> g[maxn];

void djk(int st, int dist[])
{
    priority_queue <ii, vector <ii>, greater <ii>> q;
    for (int i = 1; i <= n; i++) dist[i] = oo;
    dist[st] = 0;
    q.push({0, st});

    while(!q.empty()) {
        int cost = q.top().fi, z = q.top().se;
        q.pop();
        if (cost > dist[z]) continue;

        for (auto e : g[z]) {
            int x = e.fi, y = e.se;
            if (dist[x] > dist[z] + y) {
                dist[x] = dist[z] + y;
                q.push({dist[x], x});
            }
        }
    }
}
iii ed[maxn];

vector <int> adj[maxn], ans;


int vs[maxn], dp1[maxn], dp2[maxn];
void dfs(int u) {
	vs[u] = 1;
	for (int x : adj[u]) {
		if (!vs[x])
			dfs(x);
	}
	vs[u] = 2;
	ans.pb(u);
}
main() {
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    if(fopen(task".inp","r")) {
        freopen(task".inp","r",stdin);
        freopen(task".out","w",stdout);
    }
    cin >> n >> m >> s >> t >> u >> v;
    for (int i = 1; i <= m; i++) {
        int l, r, z;
        cin >> l >> r >> z;
        g[l].pb({r, z});
        g[r].pb({l, z});
        ed[i] = {l, {r, z}};
    }

    djk(s, dists);
    djk(t, distt);
    djk(u, distu);
    djk(v, distv);

//    cout << dists[6] << endl;
    for (int i = 1; i <= m; i++) {
        int l = ed[i].fi, r = ed[i].se.fi, z = ed[i].se.se;

        if (dists[l] + z + distt[r] == dists[t]) {
            adj[r].pb(l);
//            cout << l << " " << r << endl;
        }
        else if (dists[r] + z + distt[l] == dists[t]) {
            adj[l].pb(r);
        }
    }

    for (int i = 1; i <= n; i++) {
		if (!vs[i]) dfs(i);
	}

  //  cout << distu[1] << " " << distv[5] << endl;
    int mini = distu[v];
    for (int b : ans) {
        dp1[b] = distu[b], dp2[b] = distv[b];

        for (int a : adj[b]) {
            mini = min({mini, dp1[a] + distv[b], dp2[a] + distu[b]});
            dp1[b] = min(dp1[b], dp1[a]);
            dp2[b] = min(dp2[b], dp2[a]);
        }
    }

    cout << mini;
}

Compilation message (stderr)

commuter_pass.cpp:77:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   77 | main() {
      | ^~~~
commuter_pass.cpp: In function 'int main()':
commuter_pass.cpp:80:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   80 |         freopen(task".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
commuter_pass.cpp:81:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   81 |         freopen(task".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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