Submission #1128818

#	Time	Username	Problem	Language	Result	Execution time	Memory
1128818		Gray	Evacuation plan (IZhO18_plan)	C++20	100 / 100	566 ms	46808 KiB

plan

#include <algorithm>
#include <bits/stdc++.h>
#include <cassert>
#include <functional>
#include <iomanip>
#include <queue>
using namespace std;
#define ll long long
#define ull unsigned long long
#define ld long double
#define ff first
#define ss second
#define ln "\n"
#define mp make_pair

const ll INF = 2e18;
const ll MOD = 1e9+7;

struct DSU{
    vector<ll> p;
    vector<set<ll>> qs;
    ll n;
    DSU(ll N){
        n=N; p.resize(n+1, -1);
        qs.resize(n+1);
    }
    void add_query(ll u, ll i){
        qs[u].insert(i);
    }
    ll get(ll u){
        return p[u]==-1?u:p[u]=get(p[u]);
    }
    set<ll> unite(ll u, ll v){
        u=get(u); v=get(v);
        if (u==v) return set<ll>();
        if (qs[u].size()<qs[v].size()) swap(u, v);
        p[v]=u;
        set<ll> ret;
        for (auto i:qs[v]){
            if (qs[u].count(i)){
                qs[u].erase(i);
                ret.insert(i);
            }else{
                qs[u].insert(i);
            }
        }
        qs[v].clear();
        return ret;
    }
};

struct edge{
    ll u, v, w;
};
ll n, m;
vector<vector<ll>> A;
vector<edge> e;
vector<ll> dist, bad;

void gendist(){
    dist.assign(n+1, -1);
    priority_queue<pair<ll, ll>, vector<pair<ll, ll>>, greater<pair<ll, ll>>> que;
    for (auto ch:bad){
        que.push({0, ch});
    }
    while (!que.empty()){
        auto cur = que.top(); que.pop();
        if (dist[cur.ss]!=-1) continue;
        dist[cur.ss]=cur.ff;
        for (auto i:A[cur.ss]){
            ll v = e[i].u^e[i].v^cur.ss;
            if (dist[v]==-1) que.push({e[i].w+cur.ff, v});
        }
    }
}

void solve(){
    cin >> n >> m;
    A.assign(n+1, vector<ll>());
    e.resize(m);
    for (ll i=0; i<m; i++){
        cin >> e[i].u >> e[i].v >> e[i].w;
        A[e[i].u].push_back(i);
        A[e[i].v].push_back(i);
    }
    ll k; cin >> k; bad.resize(k);
    for (ll i=0; i<k; i++) cin >> bad[i];
    gendist();
    ll mxd = 0; for (auto ch:dist) mxd=max(mxd, ch);
    vector<pair<ll, ll>> dst;
    for (ll i=1; i<=n; i++){
        dst.push_back({dist[i], i});
    }
    sort(dst.begin(), dst.end());

    DSU tr(n);
    ll q; cin >> q;
    vector<ll> res(q);
    for (ll i=0; i<q; i++){
        ll u, v; cin >> u >> v;
        tr.add_query(u, i);
        tr.add_query(v, i);
    }
    vector<ll> usable(n+1);
    ll cur = mxd+1;
    while (!dst.empty()){
        while (!dst.empty() and dst.back().ff>=cur){
            ll proc = dst.back().ss;
            dst.pop_back();
            for (auto i:A[proc]){
                ll v = e[i].u^e[i].v^proc;
                if (usable[v]){
                    set<ll> comp = tr.unite(proc, v);
                    for (auto qs:comp){
                        res[qs]=cur;
                    }
                }
            }
            usable[proc]=1;
        }
        cur--;
    }
    for (ll i=0; i<q; i++){
        cout << res[i] << ln;
    }
}

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    auto start = chrono::high_resolution_clock::now();
    ll t=1;
    // cin >> t;
    while (t--) solve();
    #ifdef LOCAL
    auto duration = chrono::duration_cast<chrono::microseconds>(chrono::high_resolution_clock::now() - start);
    cout << setprecision(0) << fixed << "time: " << (double)duration.count()/1000.0 << " milliseconds" << endl;
    #endif
}

• Subtask 1: 10 / 10
• Subtask 2: 13 / 13
• Subtask 3: 12 / 12
• Subtask 4: 19 / 19
• Subtask 5: 46 / 46