Submission #1274018

#	Time	Username	Problem	Language	Result	Execution time	Memory
1274018		quanduongxuan12	Commuter Pass (JOI18_commuter_pass)	C++20	15 / 100	2093 ms	30172 KiB

commuter_pass

#include <bits/stdc++.h>
using namespace std;
#define name "commuter"
#define MAXN 200005
#define pb push_back
#define pf push_front
#define ll long long
#define ii pair<int, int>
#define fs first
#define sc second
#define ill pair<int, ll>
#define lli pair<ll, int>
#define llll pair<ll, ll>
#define all(v) v.begin(),v.end()
#define uni(v) v.erase(unique(all(v)),v.end())
#define bit(n,i) (((n)>>(i))&1)
#define FOR(i,a,b) for (int i=(a),_b=(b); i<=_b; i++)
#define FORD(i,a,b) for (int i=(a),_b=(b); i>=_b; i--)
#define MASK(i) (1LL<<(i))
const ll INF=1e18;
const int MOD=1e9+7;
void add(int &u, int v){
    u+=v;
    if (u>=MOD) u-=MOD;
}
void sub(int &u, int v){
    u-=v;
    if (u<0) u+=MOD;
}
void minimize(ll &u, ll v){
    u=min(u,v);
}
void maximize(int &u, int v){
    u=max(u,v);
}
long long Rand(long long l, long long r){
    ll tmp=0;
    FOR(i,1,4) tmp=((tmp<<15)^(((1<<15)-1)&rand()));
    return l+tmp%(r-l+1);
}
int n,m;
vector<ii> adj[MAXN];
vector<int> child[MAXN],par[MAXN];
int S,T,U,V;
ll d[3][MAXN];
bool visited[MAXN];
priority_queue<lli,vector<lli>,greater<lli>> pq;
void dijkstra(int type, int s){
    FOR(i,1,n) d[type][i]=INF;
    d[type][s]=0;
    pq.push({0,s});
    while (pq.size()){
        lli tmp=pq.top();
        pq.pop();
        int u=tmp.sc;
        if (visited[u]) continue;
        visited[u]=1;
        for (ii pairs:adj[u]){
            int v=pairs.fs;
            int wei=pairs.sc;
            if (d[type][v]>d[type][u]+1LL*wei){
                d[type][v]=d[type][u]+1LL*wei;
                pq.push({d[type][v],v});
            }
        }
    }
}
ll ans;
ll f[MAXN],g[MAXN];
void dfs(int type, int u){
    if (type==1){
        for (int v:child[u]){
            f[v]=min(f[u],d[1][v]);
            dfs(type,v);
        }
    }
    else{
        for (int v:par[u]){
            g[v]=min(g[u],d[2][v]);
            dfs(type,v);
        }
    }
}
struct edge{
    int u,v,w;
}e[MAXN];
int Par[MAXN],lab[MAXN];
int main()
{
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    /*
    srand(time(0));
    n=Rand(1000,1000);
    S=Rand(1,n);
    T=Rand(1,n);
    U=Rand(1,n);
    V=Rand(1,n);
    FOR(i,2,n) Par[i]=Rand(max(1LL,i-5),i-1);
    FOR(i,1,n) lab[i]=i;
    random_shuffle(lab+1,lab+n+1);
    vector<ii> edges;
    FOR(i,2,n){
        int x=lab[i],y=lab[Par[i]];
        if (rand()%2) swap(x,y);
        edges.pb((ii){x,y});
    }
    m=Rand(200000,200000);
    FOR(i,n,m){
        int x=Rand(1,n);
        int y=Rand(1,n);
        edges.pb((ii){x,y});
    }
    random_shuffle(all(edges));
    FOR(i,1,m){
        e[i].u=edges[i-1].fs;
        e[i].v=edges[i-1].sc;
        e[i].w=Rand(1,3);
    }
    cout<<n<<" "<<m<<"\n";
    cout<<S<<" "<<T<<" "<<U<<" "<<V<<"\n";
    FOR(i,1,m) cout<<e[i].u<<" "<<e[i].v<<" "<<e[i].w<<"\n";
    */
    cin>>n>>m;
    cin>>S>>T;
    cin>>U>>V;
    FOR(i,1,m) cin>>e[i].u>>e[i].v>>e[i].w;
    FOR(i,1,m){
        int u=e[i].u,v=e[i].v,w=e[i].w;
        adj[u].pb({v,w});
        adj[v].pb({u,w});
    }
    dijkstra(0,S);
    FOR(i,1,n) visited[i]=0;
    dijkstra(1,U);
    FOR(i,1,n) visited[i]=0;
    dijkstra(2,V);
    FOR(i,1,n) visited[i]=0;
    queue<int> Q;
    Q.push(T);
    while (Q.size()){
        int u=Q.front();
        Q.pop();
        for (ii pairs:adj[u]){
            int v=pairs.fs;
            int w=pairs.sc;
            if (d[0][v]==d[0][u]-1LL*w){
                par[u].pb(v);
                child[v].pb(u);
                if (!visited[v]){
                    Q.push(v);
                    visited[v]=1;
                }
            }
        }
    }
    ll ans=d[1][V];
    memset(f,0x3f,sizeof(f));
    memset(g,0x3f,sizeof(g));
    f[S]=d[1][S];
    g[T]=d[2][T];
    dfs(1,S);
    dfs(2,T);
    FOR(i,1,n) minimize(ans,f[i]+g[i]);
    ///
    memset(f,0x3f,sizeof(f));
    memset(g,0x3f,sizeof(g));
    swap(S,T);
    FOR(i,1,n) swap(par[i],child[i]);
    f[S]=d[1][S];
    g[T]=d[2][T];
    dfs(1,S);
    dfs(2,T);
    FOR(i,1,n) minimize(ans,f[i]+g[i]);
    cout<<ans;
    return 0;
}

• Subtask 1: 0 / 16
• Subtask 2: 15 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 45