Submission #998748

#	Time	Username	Problem	Language	Result	Execution time	Memory
998748		mdn2002	Closing Time (IOI23_closing)	C++17	43 / 100	933 ms	86100 KiB

closing

/*
Mayoeba Yabureru
*/
#include "closing.h"
#include<bits/stdc++.h>
using namespace std;

int max_score(int n, int x, int y, long long k, vector<int> U, vector<int> V, vector<int> W) {
    x ++, y ++;
    vector dis(n + 1, vector<long long>(2));
    vector<vector<pair<int, long long>>> gr(n + 1);

    for (int i = 0; i < n - 1; i ++) {
        int u = U[i] + 1, v = V[i] + 1, w = W[i];
        gr[u].push_back({v, w});
        gr[v].push_back({u, w});
    }

    function<void(int, int, int)> dfs = [&] (int v, int p, int wt) {
        for (auto [u, w] : gr[v]) {
            if (u == p) continue;
            dis[u][wt] = dis[v][wt] + w;
            dfs(u, v, wt);
        }
    };
    dfs(x, 0, 0), dfs(y, 0, 1);

    long long minstart = 0, min = 1e15;
    for (int i = 1; i <= n; i ++) {
        if (max(dis[i][0], dis[i][1]) < min) {
            minstart = i;
            min = max(dis[i][0], dis[i][1]);
        }
    }

    multiset<pair<long long, int>> ms;

    vector<int> did(n + 1);
    int ans = 0;

    function f = [&] {
        multiset<pair<long long, int>> s;
        for (int i = 1; i <= n; i ++) {
            if (did[i]) continue;
            s.insert({dis[i][0], i});
            s.insert({dis[i][1], i});
        }
        int cnt = 0;
        vector<int> v;
        function<void(int, int)> go = [&] (int xx, int p) {
            v.push_back(xx);
            if (xx == x) {
                for (auto u : v) {
                    if (did[u] == 0) {
                        did[u] = 1;
                        k -= dis[u][0];
                        cnt ++;
                    }
                }
            }
            if (xx == y) {
                for (auto u : v) {
                    if (did[u] == 0) {
                        did[u] = 1;
                        k -= dis[u][1];
                        cnt ++;
                    }
                }
            }
            for (auto [u, w] : gr[xx]) {
                if (u == p) continue;
                go(u, xx);
            }
            v.pop_back();
        };
        if (s.size() != 2 * n) go(minstart, 0);

        while (s.size()) {
            auto [x, y] = *s.begin();
            s.erase(s.begin());
            if (did[y]) continue;
            if (x > k) break;
            k -= x;
            did[y] = 1;
            cnt ++;
        }
        if (k >= 0) return cnt;
        return -100000000;
    };

    long long kk = k;
    ans = f();

    for (int i = 1; i <= n; i ++) did[i] = 0;
    int cnt = 0;
    k = kk;

    for (int i = 1; i <= n; i ++) ms.insert({max(dis[i][0], dis[i][1]), i});

    while (ms.size()) {
        vector<int> odid = did;
        long long kk = k;
        ans = max(ans, cnt + f());

        did = odid;
        k = kk;
        auto [x, y] = *ms.begin();
        ms.erase(ms.begin());
        if (x > k) break;
        k -= x;
        did[y] = 2;
        cnt += 2;
    }

    return ans;
}
/*
2
7 0 2 10
0 1 2
0 3 3
1 2 4
2 4 2
2 5 5
5 6 3

4 0 3 20
0 1 18
1 2 1
2 3 19
*/

Compilation message (stderr)

closing.cpp: In lambda function:
closing.cpp:76:22: warning: comparison of integer expressions of different signedness: 'std::multiset<std::pair<long long int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   76 |         if (s.size() != 2 * n) go(minstart, 0);
      |             ~~~~~~~~~^~~~~~~~

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