Submission #1274015

#TimeUsernameProblemLanguageResultExecution timeMemory
1274015quanduongxuan12Commuter Pass (JOI18_commuter_pass)C++20
0 / 100
2095 ms33988 KiB
#include <bits/stdc++.h>
using namespace std;
#define name "commuter"
#define int long long
#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){
                if (type==0){
                    if (d[type][v]>d[type][u]+1LL*wei){
                        par[v].clear();
                    }
                    par[v].pb(u);
                }
                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];
int32_t main()
{
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    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);
    visited[T]=1;
    while (Q.size()){
        int u=Q.front();
        Q.pop();
        for (int p:par[u]){
            child[p].pb(u);
            if (!visited[p]){
                visited[p]=1;
                Q.push(p);
            }
        }
    }
    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);
    return 0;
    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;
}
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