Submission #875801

#	Time	Username	Problem	Language	Result	Execution time	Memory
875801		Beerus13	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	244 ms	24112 KiB

commuter_pass

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<ll, int>
#define fi first
#define se second
const int ar = 1e5 + 5;
int n, m, u, v, s, t;
ll dp[ar][2], dis[ar][2], d[ar];
vector<pii> adj[ar];
ll ans = 1e18;

void dijktra(int u, int c) {
    priority_queue<pii, vector<pii>, greater<pii>> q;
    q.push({0, u});
    dp[u][c] = 0;
    while(q.size()) {
        int vt = q.top().se; ll kc = q.top().fi; q.pop();
        if(kc > dp[vt][c]) continue;
        for(auto x : adj[vt]) {
            if(dp[x.se][c] > dp[vt][c] + x.fi) {
                dp[x.se][c] = dp[vt][c] + x.fi;
                q.push({dp[x.se][c], x.se});
            }
        }
    }
}

void dijktra2(int u) {
    memset(dis, 0x3f, sizeof(dis));
    memset(d, 0x3f, sizeof(d));
    priority_queue<pii, vector<pii>, greater<pii>> q;
    q.push({0, u});
    dis[u][0] = dp[u][0];
    dis[u][1] = dp[u][1];
    d[u] = 0;
    while(q.size()) {
        int vt = q.top().se, pa = q.top().se; ll kc = q.top().fi; q.pop();
        if(kc > d[vt]) continue;
        for(auto x : adj[vt]) {
            if(d[x.se] > d[vt] + x.fi) {
                d[x.se] = d[vt] + x.fi;
                dis[x.se][0] = min(dp[x.se][0], dis[vt][0]);
                dis[x.se][1] = min(dp[x.se][1], dis[vt][1]);
                q.push({d[x.se], x.se});
            }
            else if(d[x.se] == d[vt] + x.fi) {
                if(min(dp[x.se][0], dis[vt][0]) + min(dp[x.se][1], dis[vt][1]) <= dis[x.se][0] + dis[x.se][1]) {
                    dis[x.se][0] = min(dp[x.se][0], dis[vt][0]);
                    dis[x.se][1] = min(dp[x.se][1], dis[vt][1]);
                }
            }
        }
    }
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    cin >> n >> m >> s >> t >> u >> v;
    for(int i = 1; i <= m; ++i) {
        int x, y, w; cin >> x >> y >> w;
        adj[x].push_back({w, y});
        adj[y].push_back({w, x});
    }
    memset(dp, 0x3f, sizeof(dp));
    dijktra(u, 0);
    dijktra(v, 1);
    ans = dp[v][0];
    dijktra2(s);
    ans = min(ans, dis[t][0] + dis[t][1]);
    dijktra2(t);
    ans = min(ans, dis[s][0] + dis[s][1]);
    cout << ans;
}

Compilation message (stderr)

commuter_pass.cpp: In function 'void dijktra2(int)':
commuter_pass.cpp:38:30: warning: unused variable 'pa' [-Wunused-variable]
   38 |         int vt = q.top().se, pa = q.top().se; ll kc = q.top().fi; q.pop();
      |                              ^~

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