Submission #946380

#	Time	Username	Problem	Language	Result	Execution time	Memory
946380		vjudge1	Commuter Pass (JOI18_commuter_pass)	C++17	55 / 100	214 ms	23260 KiB

commuter_pass

//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
//#pragma GCC optimize("Ofast,unroll-loops,fast-math,O3")

#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <cassert>
#include <iomanip>
#include <iostream>
#include <algorithm>
#include <stdio.h>
#include <fstream>
#include <unordered_map>
#define ll long long
#define int long long
#define all(v) v.begin(), v.end()
#define nl '\n'
#define pb push_back
#define sz(s) (int)(s).size()
#define f first
#define s second
using namespace std;
const ll N = 1e5 + 50, MX = 1e18;
bool was[N];
void solve(){
    ll n,m;
    cin >> n >> m;
    vector <pair <int, int> > g[n + 1];
    ll s, t, u, v;
    cin >> s >> t >> u >> v;
    for(int i = 1; i <= m; i++){
        ll a, b, x;
        cin >> a >> b >> x;
        g[a].pb({b,x});
        g[b].pb({a, x});
    }
    if(s == u){
        ll ds[n + 1], dt[n + 1];
        if(true){
            for (int j = 1; j <= n; j++) {
                ds[j] = MX;
            }
            ds[s]=0;
            priority_queue< pair<long long, int> > st;
            st.push({0, s});
            while(st.size() != 0) {
                int curv = st.top().second;
                st.pop();
                if(was[curv]) continue;
                was[curv] = 1;
                for(auto [to, w]: g[curv]) {
                    if(ds[to] > ds[curv] + w) {
                        //s.erase({d[to], to});
                        ds[to] = ds[curv] + w;
                        st.push({-ds[to], to});
                    }
                }
            }
            //cout << ds[v] << nl;
        }
        if(true){
            for (int j = 1; j <= n; j++) {
                dt[j] = MX;
                was[j]=0;
            }
            dt[t]=0;
            priority_queue< pair<long long, int> > s;
            s.push({0, t});
            while(s.size() != 0) {
                int curv = s.top().second;
                s.pop();
                if(was[curv]) continue;
                was[curv] = 1;
                for(auto [to, w]: g[curv]) {
                    //cout << to << " " << w << " " << curv << nl;
                    if(dt[to] > dt[curv] + w) {
                        //s.erase({d[to], to});
                        dt[to] = dt[curv] + w;
                        s.push({-dt[to], to});
                    }
                }
            }
        }
        for(int i = 1; i <= n; i++){
            //cout << i << " " << ds[i] << " " << dt[i] << nl;
            if(ds[i] + dt[i] == ds[t]) {
                for (int j = 0; j < sz(g[i]); j++) {
                    ll x = g[i][j].f;
                    if (dt[x] + ds[x] == ds[t]) {
                        g[i][j].s=0;
                    }
                }
            }
        }
        if(true){
            for (int j = 1; j <= n; j++) {
                was[j]=0;
            }
            ds[s]=0;
            priority_queue< pair<long long, int> > st;
            st.push({0, s});
            while(st.size() != 0) {
                int curv = st.top().second;
                st.pop();
                if(was[curv]) continue;
                was[curv] = 1;
                for(auto [to, w]: g[curv]) {
                    if(ds[to] > ds[curv] + w) {
                        //s.erase({d[to], to});
                        ds[to] = ds[curv] + w;
                        st.push({-ds[to], to});
                    }
                }
            }
            cout << ds[v] << nl;
        }
    }
    else if(n <= 300) {
        ll d[n+1][n + 1];
        for(int i = 1; i <= n; i++) {
            for (int j = 1; j <= n; j++) {
                d[i][j] = MX;
            }
        }
        for(int i = 1; i <= n; i++){
            for (int j = 1; j <= n; j++) {
                was[j] = 0;
            }
            d[i][i] = 0;
            priority_queue< pair<long long, int> > s;
            s.push({0, i});
            while(s.size() != 0) {
                int curv = s.top().second;
                s.pop();
                if(was[curv]) continue;
                was[curv] = 1;
                for(auto [to, w]: g[curv]) {
                    if(i == 6){
                        //cout << d[i][to] << ' ' << to << " " << w << " " << d[i][v] << " " << v << nl;
                    }
                    if(d[i][to] > d[i][curv] + w) {
                        //s.erase({d[to], to});
                        d[i][to] = d[i][curv] + w;
                        s.push({-d[i][to], to});
                    }
                }
            }
        }
        ll ans = d[u][v];
        //cout << d[s][t] << nl;
        //cout << ds[3] << " " << dt[5] << nl;
        for (int i = 1; i <= n; i++) {
            for (int j = 1; j <= n; j++) {
                if (d[s][i] + d[t][j] + d[i][j] == d[s][t] || d[s][j] + d[t][i] + d[i][j] == d[s][t]) {
                    ans = min(ans, d[u][i] + d[v][j]);
                }
            }
        }
        cout << ans << nl;
    }
    else{
        ll ds[n + 1], p[n + 1], du[n + 1], dv[n + 1];
        if(true){
            for (int j = 1; j <= n; j++) {
                ds[j] = MX;
            }
            ds[s]=0;
            priority_queue< pair<long long, int> > st;
            st.push({0, s});
            p[s]=0;
            while(st.size() != 0) {
                int curv = st.top().second;
                st.pop();
                if(was[curv]) continue;
                was[curv] = 1;
                for(auto [to, w]: g[curv]) {
                    if(ds[to] > ds[curv] + w) {
                        //s.erase({d[to], to});
                        p[to] = curv;
                        ds[to] = ds[curv] + w;
                        st.push({-ds[to], to});
                    }
                }
            }
            //cout << ds[v] << nl;
        }
        if(true){
            for (int j = 1; j <= n; j++) {
                was[j]=0;
                du[j]=MX;
            }
            du[u]=0;
            priority_queue< pair<long long, int> > st;
            st.push({0, u});
            while(st.size() != 0) {
                int curv = st.top().second;
                st.pop();
                if(was[curv]) continue;
                was[curv] = 1;
                for(auto [to, w]: g[curv]) {
                    if(du[to] > du[curv] + w) {
                        //s.erase({d[to], to});
                        du[to] = du[curv] + w;
                        st.push({-du[to], to});
                    }
                }
            }
        }
        if(true){
            for (int j = 1; j <= n; j++) {
                was[j]=0;
                dv[j]=MX;
            }
            dv[v]=0;
            priority_queue< pair<long long, int> > st;
            st.push({0, v});
            while(st.size() != 0) {
                int curv = st.top().second;
                st.pop();
                if(was[curv]) continue;
                was[curv] = 1;
                for(auto [to, w]: g[curv]) {
                    if(dv[to] > dv[curv] + w) {
                        //s.erase({d[to], to});
                        dv[to] = dv[curv] + w;
                        st.push({-dv[to], to});
                    }
                }
            }
        }
        vector <int> path;
        ll x = t;
        while(x != 0){
            path.pb(x);
            x = p[x];
        }
        ll mnv=MX, mnu=MX;
        for(auto x:path){
            //cout << x << " ";
            mnv = min(dv[x], mnv);
            mnu = min(du[x], mnu);
        }
        //cout << du[v] << nl;
        cout << min(mnv + mnu, dv[u]);
    }
}
signed main(){
    //freopen("lca.in", "r", stdin);
    //freopen("lca.out", "w", stdout);
    ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    ll ql=1;
    //cin >> ql;
    //tst++;
    while(ql--){
        solve();
    }
}

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