제출 #1348107

#제출 시각아이디문제언어결과실행 시간메모리
1348107baodatEvacuation plan (IZhO18_plan)C++20
22 / 100
4091 ms29212 KiB
#include <bits/stdc++.h>
using namespace std;
#define ll long long 
#define FOR(i, l, r) for(int i = l; i <= r; i++)
#define FORD(i, l, r) for(int i = l; i >= r; i--)
#define db double
#define ldb long double
#define all_1(x) (x).begin() + 1, (x).end()
#define all(x) (x).begin(), (x).end()
#define ins insert
#define pb push_back
template<typename T>void debug_var(const T& var, const string& name){
    cerr << name << ": " << var << "\n";
}
template<typename T>void debug_1d(const T& vt, const string& name){
    if(vt.empty()){
        cerr << name << " is empty!\n";
        return;
    }
    FOR(i, 0, (int)vt.size() - 1){
        cerr << name << "[" << i << "]: " << vt[i] << "\n";
    }
}
struct Edge{
    int u, v, w;
};
struct DSU{
    int _n;
    vector<int> _par, _rnk;
    DSU(int n = 0){
        init(n);
    }
    void init(int n){
        _n = n;
        _par.assign(n + 1, 0);
        _rnk.assign(n + 1, 0);
        iota(all(_par), 0);
    }
    int find_u(int u){
        return u == _par[u] ? u : _par[u] = find_u(_par[u]);
    }
    bool unite(int u, int v){
        u = find_u(u);
        v = find_u(v);
        if(u == v) return true;
        if(_rnk[u] < _rnk[v]) swap(u, v);
        if(_rnk[u] == _rnk[v]) ++_rnk[u];
        _par[v] = u;
        return true;
    }
};
const int N = 1e5 + 5;
const int LOG = 20;
vector<pair<int, int>> adj[N];
int krt_w[2 * N], danger[N];
int n, m, k, depth[2 * N], lca[N][LOG];
vector<int> dist, krt[2 * N];
void dijkstra(){
    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
    FOR(i, 1, k){
        pq.push({0, danger[i]});
        dist[danger[i]] = 0;
    }
    while(!pq.empty()){
        auto [dist_u, u] = pq.top();
        pq.pop();
        if(dist_u != dist[u]) continue;
        for(auto [v, w] : adj[u]){
            if(dist[v] > dist[u] + w){
                dist[v] = dist[u] + w;
                pq.push({dist[v], v});
            }
        }
    }
}
void dfs(int u, int p){
    for(int v : krt[u]){
        if(v == p) continue;
        depth[v] = depth[u] + 1;
        lca[v][0] = u;
        FOR(j, 1, LOG - 1) lca[v][j] = lca[lca[v][j - 1]][j - 1];
        dfs(v, u);
    }
}
int lift(int u, int k){
    FOR(j, 0, LOG - 1) if(k & (1 << j)) u = lca[u][j];
    return u;
}
int LCA(int u, int v){
    if(depth[u] != depth[v]){
        if(depth[u] < depth[v]) swap(u, v);
        u = lift(u, depth[u] - depth[v]);
    }
    if(u == v) return u;
    FORD(j, LOG - 1, 0) if(lca[u][j] != lca[v][j]){
        u = lca[u][j];
        v = lca[v][j];
    }
    return lca[u][0];
}
void solve(){
    cin >> n >> m;
    dist.assign(n + 1, 2e9);
    FOR(i, 1, m){
        int u, v, w;
        cin >> u >> v >> w;
        adj[u].pb({v, w});
        adj[v].pb({u, w});
    }
    cin >> k;
    FOR(i, 1, k) cin >> danger[i];
    dijkstra();

    //debug_1d(dist, "dist");
    vector<Edge>edges;
    FOR(u, 1, n){
        for(auto [v, w] : adj[u]){
            if(u < v) edges.pb({u, v, min(dist[u], dist[v])});
        }
    }
    sort(all(edges), [&](Edge a, Edge b){
        return a.w > b.w;
    });
    //krt build here
    int amount_node = n;
    DSU dsu(2 * n);
    vector<int> active(2 * n + 1, 0);
    iota(all(active), 0);
    for(auto e : edges){
        int u = dsu.find_u(e.u);
        int v = dsu.find_u(e.v);
        if(u != v){
            ++amount_node;
            krt_w[amount_node] = e.w;
            krt[amount_node].pb(active[u]);
            krt[amount_node].pb(active[v]);
            dsu.unite(u, v);
            active[dsu.find_u(u)] = amount_node;
        }
    }
    FOR(i ,1, amount_node){
        if(active[dsu.find_u(i)] == i && depth[i] == 0) dfs(i, -1);
    }
    int q;
    cin >> q;
    while(q--){
        int s, t;
        cin >> s >> t;
        cout << krt_w[LCA(s, t)] << "\n";
    }
}
signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int t = 1;
    //cin >> t;
    while(t--){
        solve();
    }
    return 0;
}
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