Submission #52304

#	Time	Username	Problem	Language	Result	Execution time	Memory
52304		evpipis	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	1512 ms	70656 KiB

commuter_pass

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

#define fi first
#define se second
#define pb push_back
#define mp make_pair
typedef long long ll;
typedef pair<int, int> ii;

const int len = 1e5+5;
const ll inf = 1e16;
int n, m, s1, t1, s2, t2, best[len];
ll dis[5][len];
vector<ii> adj[len];
priority_queue<pair<ll, ii>, vector<pair<ll, ii> >, greater<pair<ll, ii> > > pq;

void dfs(int u){
    //printf("best %d\n", u);
    best[u] = 1;
    for (int j = 0; j < adj[u].size(); j++){
        ii v = adj[u][j];
        if (!best[v.fi] && dis[4][v.fi]+v.se == dis[4][u])
            dfs(v.fi);
    }
}

void path(int s, int hey){
    if (!hey){
        for (int j = 1; j <= n; j++)
            dis[4][j] = inf;
    }
    else{
        for (int i = 0; i < 4; i++)
            for (int j = 1; j <= n; j++)
                dis[i][j] = inf;
    }

    if (!hey){
        pq.push(mp(0, mp(4, s)));
    }
    else{
        pq.push(mp(0, mp(0, s)));
        if (best[s])
            pq.push(mp(0, mp(1, s))), pq.push(mp(0, mp(2, s)));
    }

    while (!pq.empty()){
        pair<ll, ii> top = pq.top();
        pq.pop();

        int t = top.se.fi, u = top.se.se;
        ll d = top.fi;

        if (dis[t][u] != inf)
            continue;
        dis[t][u] = d;

        //printf("(%d, %d) -> %lld\n", t, u, d);

        for (int j = 0; j < adj[u].size(); j++){
            ii v = adj[u][j];
            if (t == 0){
                pq.push(mp(d+v.se, mp(0, v.fi)));
                if (best[v.fi])
                    pq.push(mp(d+v.se, mp(1, v.fi))), pq.push(mp(d+v.se, mp(2, v.fi)));
            }
            else if (t == 1){
                pq.push(mp(d+v.se, mp(3, v.fi)));
                if (best[v.fi] && dis[4][u]-dis[4][v.fi] == (ll)v.se)
                    pq.push(mp(d, mp(1, v.fi)));
            }
            else if (t == 2){
                pq.push(mp(d+v.se, mp(3, v.fi)));
                if (best[v.fi] && dis[4][u]-dis[4][v.fi] == -(ll)v.se)
                    pq.push(mp(d, mp(2, v.fi)));
            }
            else if (t == 3){
                pq.push(mp(d+v.se, mp(3, v.fi)));
            }
            else{
                pq.push(mp(d+v.se, mp(4, v.fi)));
            }
        }
    }
}

int main(){
    scanf("%d %d %d %d %d %d", &n, &m, &s1, &t1, &s2, &t2);
    for (int i = 0; i < m; i++){
        int a, b, c;
        scanf("%d %d %d", &a, &b, &c);
        adj[a].pb(mp(b, c));
        adj[b].pb(mp(a, c));
    }

    path(s1, 0);
    dfs(t1);
    path(s2, 1);

    ll ans = min(min(dis[0][t2], dis[1][t2]), min(dis[2][t2], dis[3][t2]));
    printf("%lld\n", ans);
    return 0;
}

Compilation message (stderr)

commuter_pass.cpp: In function 'void dfs(int)':
commuter_pass.cpp:21:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int j = 0; j < adj[u].size(); j++){
                     ~~^~~~~~~~~~~~~~~
commuter_pass.cpp: In function 'void path(int, int)':
commuter_pass.cpp:61:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int j = 0; j < adj[u].size(); j++){
                         ~~^~~~~~~~~~~~~~~
commuter_pass.cpp: In function 'int main()':
commuter_pass.cpp:89:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d %d %d %d %d", &n, &m, &s1, &t1, &s2, &t2);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
commuter_pass.cpp:92:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d %d", &a, &b, &c);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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