Submission #479840

#	Time	Username	Problem	Language	Result	Execution time	Memory
479840		ponytail	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	628 ms	37624 KiB

commuter_pass

#include <bits/stdc++.h>
#define int long long
using namespace std;
int dist[4][100001];
bool cmp(int a, int b) {
    return dist[0][a] < dist[0][b];
}
void solve() {
    int N, M; cin >> N >> M;
    int S[4]; cin >> S[0] >> S[1] >> S[2] >> S[3];
    vector<pair<int, int> > adj[N+1];
    for(int i=0; i<M; i++) {
        int A, B, C; cin >> A >> B >> C;
        adj[A].push_back({B, C});
        adj[B].push_back({A, C});
    }
    int vis[4][N+1];
    for(int i=1; i<=N; i++) {
        dist[0][i] = dist[1][i] = dist[2][i] = dist[3][i] = 1e18;
        vis[0][i] = vis[1][i] = vis[2][i] = vis[3][i] = 0;
    }
    for(int i=0; i<2; i++) {
        dist[i][S[i]] = 0;
        priority_queue<pair<int, int>, vector<pair<int,int> >, greater<pair<int, int> > > pq;
        for(int j=1; j<=N; j++) {
            pq.push({dist[i][j], j});
        }
        while(pq.size()) {
            pair<int, int> t= pq.top(); pq.pop();
            if(!vis[i][t.second]) {
                vis[i][t.second]=1;
                for(auto x : adj[t.second]) {
                    if(!vis[i][x.first] && dist[i][x.first] > dist[i][t.second] + x.second) {
                        dist[i][x.first] = dist[i][t.second] + x.second;
                        pq.push({dist[i][x.first], x.first});
                    }
                }
            }
        }
    }
    int ans = 1e18;
    int allowed[N+1];
    for(int i=1; i<=N; i++) {
        allowed[i] = (dist[0][i] + dist[1][i] == dist[0][S[1]] ? 1 : 0);
    }
    vector<int> dag1[N+1], dag2[N+1]; // small -> big, big -> small
    for(int i=1; i<=N; i++) {
        for(int j=0; j<adj[i].size(); j++) {
            if(allowed[i] && allowed[adj[i][j].first] && dist[0][i] < dist[0][adj[i][j].first]) {
                dag1[i].push_back(adj[i][j].first);
                dag2[adj[i][j].first].push_back(i);
            }
        }
    }
    //Reset
    for(int i=2; i<4; i++) {
        dist[i][S[i]] = 0;
        priority_queue<pair<int, int>, vector<pair<int,int> >, greater<pair<int, int> > > pq;
        for(int j=1; j<=N; j++) {
            pq.push({dist[i][j], j});
        }
        while(pq.size()) {
            pair<int, int> t= pq.top(); pq.pop();
            if(!vis[i][t.second]) {
                vis[i][t.second]=1;
                for(auto x : adj[t.second]) {
                    if(!vis[i][x.first] && dist[i][x.first] > dist[i][t.second] + x.second) {
                        dist[i][x.first] = dist[i][t.second] + x.second;
                        pq.push({dist[i][x.first], x.first});
                    }
                }
            }
        }
    }
    vector<int> all;
    all.push_back(0);
    for(int i=1; i<=N; i++) {
        if(allowed[i]) all.push_back(i);
    }
    sort(all.begin() + 1, all.end(), cmp);
    int A = all.size() - 1;
    int dp[A+1];
    int pos[N+1];
    for(int i=1; i<=A; i++) {
        pos[all[i]] = i;
    }
    for(int i=1; i<=A; i++) {
        dp[i] = dist[2][all[i]];
        for(int x : dag2[all[i]]) {
            dp[i] = min(dp[i], dp[pos[x]]);
        }
        ans = min(ans, dp[i] + dist[3][all[i]]);
        
    }
    reverse(all.begin() + 1, all.end());
    for(int i=1; i<=A; i++) {
        pos[all[i]] = i;
    }
    for(int i=1; i<=A; i++) {
        dp[i] = dist[2][all[i]];
        for(int x : dag1[all[i]]) {
            dp[i] = min(dp[i], dp[pos[x]]);
        }
        ans = min(ans, dp[i] + dist[3][all[i]]);
    }
    ans = min(ans, dist[2][S[3]]);
    cout << ans << '\n';
} 
signed main() {
    int t = 1;// cin >> t;
    while(t--) solve();
}
//6 -> 3 -> 1 -> 8 -> 9
//  12   1    1    1

Compilation message (stderr)

commuter_pass.cpp: In function 'void solve()':
commuter_pass.cpp:48:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   48 |         for(int j=0; j<adj[i].size(); j++) {
      |                      ~^~~~~~~~~~~~~~

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