Submission #893043

#	Time	Username	Problem	Language	Result	Execution time	Memory
893043		vjudge1	Evacuation plan (IZhO18_plan)	C++17	29 / 100	4073 ms	72760 KiB

plan

// 以上帝的名义
// 候选硕士
#include <bits/stdc++.h>

#ifdef local
#include "algo/debug.h"
#else
#define dbg(x...) 0
#endif

using namespace std ;
using ll = long long ;

#define int ll

template<class T> constexpr T inf = ::numeric_limits<T>::max() / 32 * 15 + 208;

const int N = 1e6 + 5 ;

int n , m , k , city[N] ;
ll dist[N], pr[N] ;
vector<pair<ll,int>> g[N] ;

void djickstra() {
    for (int i = 1 ; i <= n ; i++) {
        dist[i] = inf<ll> ;
    }
    set<pair<ll,int>> st;
    for (int i = 0 ; i < k ; i++) {
        st.insert({0, city[i]}) ;
        dist[city[i]] = 0 ;
    }
    while (st.size()) {
        auto [val, v] = *st.begin() ;
        st.erase(st.begin()) ;
        for (auto [w, to] : g[v]) {
            if (dist[to] > dist[v] + w) {
                st.erase({dist[to], to}) ;
                dist[to] = dist[v] + w ;
                st.insert({dist[to], to}) ;
            }
        }
    }
}

struct DSU {
   vector<int> parent, sz ;
   DSU(int n) {
      parent.resize(n) ;
      iota(begin(parent), end(parent), 0) ;
      sz.assign(n, 1) ;
   }
   int find(int i) {
      if (i == parent[i]) {
         return i ;
      } else {
         return parent[i] = find(parent[i]) ;
      }
   }
   bool unite(int u, int v) {
      u = find(u), v = find(v) ;
      if (u == v) return false ;
      if (sz[v] == sz[u]) sz[v]++ ;
      if (sz[v] < sz[u]) swap(u, v) ;
      parent[u] = v ;
      return true ;
   }
   bool same(int u, int v) {
      return (find(u) == find(v)) ;
   }
};

int32_t main() {
    cin.tie(0)->sync_with_stdio(false) ;
    cin >> n >> m ;
    vector<tuple<ll,ll,ll>> edge(m) ;
    for (int i = 0 ; i < m ; i++) {
        ll u , v , w ; cin >> u >> v >> w ;
        g[u].push_back({w, v}) ;
        g[v].push_back({w, u}) ;
        edge[i] = {0, u, v} ;
    }
    cin >> k ;
    for (int i = 0 ; i < k ; i++) {
        cin >> city[i] ;
    }
    djickstra() ;
    for (int i = 0 ; i < m ; i++) {
        auto& [val, u, v] = edge[i] ;
        val = min(dist[u], dist[v]) ;
    }
    int q ; cin >> q ;
    set<tuple<int,int,int>> query ;
    for (int i = 0 ; i < q;  i++) {
        int u , v ; cin >> u >> v ;
        query.insert({u, v, i}) ;
    }
    vector<ll> ans(q) ;
    sort(edge.rbegin(), edge.rend()) ;
    DSU d(n + 1) ;
    for (auto [val, u, v] : edge) {
        if (query.empty()) break ;
        if (d.unite(u, v)) {
            for (auto it = query.begin() ; query.size() && it != query.end() ; it++) {
                auto [A, B, i] = *it ;
                if (d.same(A, B)) {
                    ans[i] = val ;
                    if (query.size() == 1) {
                        query.erase(query.begin()) ;
                    } else
                        it = query.erase(it) ;
                }
            }
        }
    }
    for (ll i : ans) {
        cout << i << "\n" ;
    }
    return 0 ;
}

// 希望白银

• Subtask 1: 10 / 10
• Subtask 2: 0 / 13
• Subtask 3: 0 / 12
• Subtask 4: 19 / 19
• Subtask 5: 0 / 46