Submission #250701

#	Time	Username	Problem	Language	Result	Execution time	Memory
250701		mat_v	Commuter Pass (JOI18_commuter_pass)	C++14	100 / 100	603 ms	23992 KiB

commuter_pass

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/rope>

#define ff(i,a,b) for(int (i) = (a); (i) <= (b); ++(i))
#define fb(i,a,b) for(int (i) = (a); (i) >= (b); --(i))
#define mod 998244353
#define xx first
#define yy second
#define all(a) (a).begin(), (a).end()
#define pb push_back
#define ll long long
#define pii pair<ll,ll>
#define N 100005

using namespace std;
using namespace __gnu_pbds;
typedef tree<int, null_type, less<int>,rb_tree_tag, tree_order_statistics_node_update> ordered_set;/// find_by_order(x)(x+1th) , order_of_key() (strictly less)
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());


int n,m;
int s,t;
int u,v;

vector<pii> graf[N];
ll dist[N][4];

void djikstra(int x, int idx){
    priority_queue<pii> pq;
    pq.push({0,x});
    ff(i,1,n){
        dist[i][idx] = 1e8;
        dist[i][idx] *= dist[i][idx];
    }
    dist[x][idx] = 0;
    while(!pq.empty()){
        pii sta = pq.top();
        pq.pop();
        int tr = sta.yy;
        ll duz = -sta.xx;
        if(dist[tr][idx] != duz)continue;
        for(auto c:graf[tr]){
            if(dist[c.xx][idx] > duz + c.yy){
                dist[c.xx][idx] = duz + c.yy;
                pq.push({-dist[c.xx][idx], c.xx});
            }
        }
    }
}


int gidx;

ll dp[N][2];
bool bio[N][2];

ll resi(int x){
    if(bio[x][gidx])return dp[x][gidx];
    bio[x][gidx] = 1;
    dp[x][gidx] = dist[x][3];
    for(auto c:graf[x]){
        if(dist[c.xx][gidx] + c.yy == dist[x][gidx]){
            dp[x][gidx] = min(dp[x][gidx], resi(c.xx));
        }
    }
    return dp[x][gidx];
}

void init(int x){
    bio[x][gidx] = 1;
    dp[x][gidx] = dist[x][3];
    ff(i,1,n){
        if(!bio[i][gidx])dp[i][gidx] = resi(i);
    }
}


int main()
{

    ios_base::sync_with_stdio(false); cin.tie(0);
    cin >> n >> m >> s >> t >> u >> v;
    ff(i,0,m - 1){
        ll a,b,c;
        cin >> a >> b >> c;
        graf[a].pb({b,c});
        graf[b].pb({a,c});
    }
    djikstra(s,0);
    djikstra(t,1);
    djikstra(u,2);
    djikstra(v,3);

    gidx = 0;
    init(s);

    gidx = 1;
    init(t);
    ll res = dist[v][2];
    ff(i,1,n){
        if(!(dist[i][0] + dist[i][1] == dist[t][0]))continue;
        res = min(res, dist[i][2] + min(dp[i][0], dp[i][1]));
    }
    cout << res << "\n";
    return 0;
}

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