Submission #781276

#	Time	Username	Problem	Language	Result	Execution time	Memory
781276		Owen11	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	315 ms	33692 KiB

commuter_pass

#include <bits/stdc++.h>
using namespace std;

# define int long long
# define fir first
# define sec second
# define pb push_back

const int cnst = 2e5+5;
bool mutipletestcase = 0;
//bool debug = false;

int n, m;
int s, t, u, v;
int shor[cnst];
int dis[cnst];
int dist[cnst];
vector<pair<int, int>> vec[cnst];

void djikstrast() {
    bool vis[n+5];
    priority_queue<tuple<int, int>, vector<tuple<int, int>>, greater<tuple<int, int>>> pq;

    pq.push({0, s});
    memset(vis, 0, sizeof(vis));

    while(!pq.empty()) {
        auto[x, idx] = pq.top(); pq.pop();

        if(vis[idx]) continue;
        vis[idx] = 1;
        dis[idx] = x;

        for(auto v: vec[idx]) {
            if(!vis[v.fir]) pq.push({x+v.sec, v.fir});
        }
    }

    pq.push({0, t});
    memset(vis, 0, sizeof(vis)); 

    while(!pq.empty()) {
        auto[x, idx] = pq.top(); pq.pop();

        if(vis[idx]) continue;
        vis[idx] = 1;
        dist[idx] = x;

        for(auto v: vec[idx]) {
            if(!vis[v.fir]) pq.push({x+v.sec, v.fir});
        }
    }

    for(int i = 1; i<=n; i++) if(dis[i]+dist[i] == dis[t]) shor[i] = 1;

    // for(int i = 1; i<=n; i++) cerr << shor[i] << " "; cerr << endl;
    // for(int i = 1; i<=n; i++) cerr << dis[i] << " "; cerr << endl;
}

void djikstrauv() {
    bool vis[n+5][5];
    memset(vis, 0, sizeof(vis));

    priority_queue<tuple<int, int, int>, vector<tuple<int, int, int>>, greater<tuple<int, int, int>>> pq;
    pq.push({0, u, 0});

    if(shor[u]) pq.push({0, u, 1}), pq.push({0, u, 2});

    while(!pq.empty()) {
        auto[x, idx, id] = pq.top(); pq.pop();

        if(vis[idx][id] || idx == 0) continue;
        vis[idx][id] = 1;

        // cerr << x << " " << idx << " " << id << endl;

        if(idx == v) {
            cout << x << endl; return;
        }

        if(id == 0) {
            for(auto v: vec[idx]) {
                if(!vis[v.fir][0]) pq.push({x+v.sec, v.fir, 0});
                if(shor[v.fir] && shor[idx]) {
                    if(!vis[v.fir][1] && dis[v.fir] < dis[idx]) pq.push({x, v.fir, 1});
                    if(!vis[v.fir][2] && dis[v.fir] > dis[idx]) pq.push({x, v.fir, 2});
                }
            }
        }
        else if(id == 1) {
            for(auto v: vec[idx]) {
                if(!vis[v.fir][3]) pq.push({x+v.sec, v.fir, 3});
                if(shor[v.fir] && dis[v.fir] < dis[idx]) pq.push({x, v.fir, 1});
            }
        }
        else if(id == 2) {
            for(auto v: vec[idx]) {
                if(!vis[v.fir][3]) pq.push({x+v.sec, v.fir, 3});
                if(shor[v.fir] && dis[v.fir] > dis[idx]) pq.push({x, v.fir, 2});
            }
        }
        else {
            for(auto v: vec[idx]) if(!vis[v.fir][3]) pq.push({x+v.sec, v.fir, 3});
        }
    }
}
 
void solve() {
    cin >> n >> m >> s >> t >> u >> v;

    for(int i = 1; i<=m; i++) {
        int a, b, c; cin >> a >> b >> c;
        vec[a].pb({b, c});
        vec[b].pb({a, c});
    }

    djikstrast();
    djikstrauv();
}

signed main() {
    ios_base::sync_with_stdio(false);
    int t = 1;
    if(mutipletestcase) cin >> t; 
    while(t--) solve();
}

Compilation message (stderr)

commuter_pass.cpp: In function 'void djikstrast()':
commuter_pass.cpp:28:13: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   28 |         auto[x, idx] = pq.top(); pq.pop();
      |             ^
commuter_pass.cpp:43:13: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   43 |         auto[x, idx] = pq.top(); pq.pop();
      |             ^
commuter_pass.cpp: In function 'void djikstrauv()':
commuter_pass.cpp:70:13: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   70 |         auto[x, idx, id] = pq.top(); pq.pop();
      |             ^

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