Submission #1061549

#	Time	Username	Problem	Language	Result	Execution time	Memory
1061549		n1k	Closing Time (IOI23_closing)	C++17	8 / 100	90 ms	40380 KiB

closing

#include "closing.h"
#include <bits/stdc++.h>

using namespace std;

using ll = long long;

int max_score(int N, int X, int Y, long long K, vector<int> U, vector<int> V, vector<int> W){
    vector<vector<array<int, 2>>> g(N);
    vector c(2, vector<ll>(N));
    vector<int> par(N);

    for(int i=0; i<N-1; i++){
        g[U[i]].push_back({V[i], W[i]});
        g[V[i]].push_back({U[i], W[i]});
    }
    function<void(int, int, vector<ll>&)> dfs = [&](int u, int p, vector<ll> &c){
        par[u] = p;
        for(auto [v, cost]:g[u]){
            if(v==p){
                continue;
            }
            c[v]+=c[u] + cost;
            dfs(v, u, c);
        }
    };

    dfs(X, -1, c[0]);
    dfs(Y, -1, c[1]);

    auto get = [&](ll K){
        int ans = 0;
        vector vis(2, vector<int>(N));
        priority_queue<array<ll, 3>, vector<array<ll, 3>>, greater<array<ll, 3>>> pq;
        // (cost, node, start x or y)
        pq.push({0, X, 0});
        pq.push({0, Y, 1});
        while(pq.size()){
            auto [cost, u, start] = pq.top();
            pq.pop();
            if(vis[start][u]){
                continue;
            }
            vis[start][u]=1;
            if(K<cost){
                break;
            }
            //cerr << u << " " << cost << " " << start << endl;
            ans++;
            K-=cost;
            for(auto [v, _]:g[u]){
                pq.push({c[start][v], v, start});
            }
        }
        return ans;
    };
    auto get2 = [&](ll K){
        int ans = 0;
        vector vis(2, vector<int>(N));
        priority_queue<array<ll, 3>, vector<array<ll, 3>>, greater<array<ll, 3>>> pq;
        priority_queue<array<ll, 2>, vector<array<ll, 2>>, greater<array<ll, 2>>> pq2;

        
        auto getnext = [&](auto u, auto start){
            array<ll, 3> best = {ll(1e9)};
            for(auto [v, _]:g[u]){
                if(vis[start^1][v] and c[start^1][v] <= c[start][v]){
                    if(not vis[start][v])
                        best = min(best, {c[start][v] - c[start^1][v], v, start});
                }else{
                    if(not vis[start][v])
                        best = min(best, {c[start][v], v, start});
                }
            }
            return best;
        };
        auto visite = [&](auto u, auto start, ll cost){
            vis[start][u]=1;
            if(cost>K) return;
            cerr << u << " " << start << " " << cost << " " << K << endl;
            K -= cost;
            ans++;
            for(auto [v, _]:g[u]){
                if(vis[start^1][v] and c[start^1][v] <= c[start][v]){
                    pq.push({c[start][v] - c[start^1][v], v, start});
                }else{
                    pq.push({c[start][v], v, start});
                }
                if(vis[start^1][v] and c[start^1][u] >= c[start][u]){
                    pq.push({c[start^1][u] - c[start][u], u, start^1});
                }
                if(vis[start^1][u]){
                    pq2.push({2 * max(c[0][v], c[1][v]) - min(c[0][v], c[1][v]), v});
                }
            }
        };
        for(int u=X; ; u=par[u]){
            if(min(c[0][u], c[1][u])>K){
                return ans;
            }
            if(c[0][u]<c[1][u]){
                visite(u, 0, c[0][u]);
            }else{
                visite(u, 1, c[1][u]);
            }
            if(u==Y) break;
        }
        cerr << K << endl;
        cerr << ans << endl;
        while(pq.size() or pq2.size()){
            vector<array<ll, 3>> todo;
            array<ll, 2> cur = {-1, -1};
            while(pq.size() and todo.size()<2){
                auto [cost, u, start] = pq.top();
                pq.pop();
                if(vis[start][u]){
                    continue;
                }
                todo.push_back({cost, u, start});
            }
            while(pq2.size() and cur[0]==-1){
                auto [cost, u]=pq2.top();
                pq2.pop();
                if(vis[0][u] or vis[1][u]) continue;
                cur = {cost, u};
            }
            // todo.size() == 1
            // todo.size() == 0
            // todo.size() == 2
            if(todo.size()==0 and cur[0]!=-1 and K>=cur[0]){
                visite(cur[1], 0, cur[0]);
                visite(cur[1], 1, 0);
            }if(todo.size()==1){
                if(cur[0]==-1){
                    visite(todo[0][1], todo[0][2], todo[0][0]);
                }else{
                    auto v = getnext(todo[0][1], todo[0][2]);
                    if(todo[0][0] + v[0] < cur[0]){
                        visite(todo[0][1], todo[0][2], todo[0][0]);
                        pq2.push(cur);
                    }else{
                        visite(cur[1], 0, cur[0]);
                        visite(cur[1], 1, 0);
                        pq.push(todo[0]);
                    }
                }
            }if(todo.size()==2){
                if(cur[0]==-1){
                    visite(todo[0][1], todo[0][2], todo[0][0]);
                    pq.push(todo[1]);
                }else{
                    auto v = getnext(todo[0][1], todo[0][2]);
                    if(todo[0][0] + min(v[0], todo[1][0]) < cur[0]){
                        visite(todo[0][1], todo[0][2], todo[0][0]);
                        pq.push(todo[1]);
                        pq2.push(cur);
                    }else{
                        visite(cur[1], 0, cur[0]);
                        visite(cur[1], 1, 0);
                        pq.push(todo[0]);
                        pq.push(todo[1]);
                    }
                }
            }
        }
        return ans;
    };
    return max(get(K), get2(K));
}

• Subtask 0: 0 / 0
• Subtask 1: 8 / 8
• Subtask 2: 0 / 9
• Subtask 3: 0 / 12
• Subtask 4: 0 / 14
• Subtask 5: 0 / 9
• Subtask 6: 0 / 11
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 17