Submission #1093787

#	Time	Username	Problem	Language	Result	Execution time	Memory
1093787		quannnguyen2009	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	383 ms	31640 KiB

commuter_pass

#include<bits/stdc++.h>
#define int long long
#define fi first
#define se second
#define pb push_back
#define ii pair<int, int>
#define sz(v) (int)v.size()
#define all(v) v.begin(), v.end()
using namespace std;

const int N=1e5+5, mod = 1e9+7, inf = 1e18;

int n, m, s, t, u, v;
vector<ii> adj[N];
vector<int> du, dv, ds;
int mxu[N], mxv[N], ans;
bool vis[N];

void cal(int src, vector<int>& d) {
    for (int i=1; i<=n; i++) vis[i] = 0;
    priority_queue<ii, vector<ii>, greater<ii>> pq;
    pq.push({0, src});
    while(!pq.empty()) {
        int dist = pq.top().fi, tmp = pq.top().se; pq.pop();
        if(!vis[tmp]) {
            d[tmp] = dist; vis[tmp] = 1;
            for (ii i: adj[tmp]) pq.push({dist+i.se, i.fi});
        }
    }
}

void cal_(int src, int des) {
    for (int i=0; i<=n; i++) { vis[i] = 0; mxu[i] = mxv[i] = inf; }
    priority_queue<pair<int, ii>> pq;
    pq.push({0, {src, 0}});
    while(!pq.empty()) {
        int dist = pq.top().fi, tmp = pq.top().se.fi, p = pq.top().se.se; pq.pop();
        if(!vis[tmp]) {
            vis[tmp] = 1; ds[tmp] = -dist;
            mxu[tmp] = min(du[tmp], mxu[p]); mxv[tmp] = min(dv[tmp], mxv[p]);
            for (ii i : adj[tmp]) pq.push({dist-i.second, {i.first, tmp}});
        } else if(-dist == ds[tmp]) {
            if(min(du[tmp], mxu[p])+min(dv[tmp], mxv[p])<=mxu[tmp]+mxv[tmp]) {
                mxu[tmp] = min(du[tmp], mxu[p]); mxv[tmp] = min(dv[tmp], mxv[p]);
            }
        }
    }
    ans = min(ans, mxu[des] + mxv[des]);
}

signed main() {
    // freopen("tmp.inp", "r", stdin);
    // freopen("tmp.out", "w", stdout);
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    cin >> n >> m >> s >> t >> u >> v;
    while(m--) {
        int a, b, c; cin >> a >> b >> c;
        adj[a].pb({b, c});
        adj[b].pb({a, c});
    }
    du.resize(n+1); dv.resize(n+1); ds.resize(n+1);
    cal(u, du); cal(v, dv); ans = du[v];
    cal_(s, t); swap(s, t); cal_(s, t);
    cout << ans;
}

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