Submission #1033767

#	Time	Username	Problem	Language	Result	Execution time	Memory
1033767		Turkhuu	Closing Time (IOI23_closing)	C++17	75 / 100	1044 ms	34592 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, ll K, vector<int> U, vector<int> V, vector<int> W) {
    vector<vector<array<int, 2>>> adj(N);
    for (int i = 0; i < N - 1; i++) {
        adj[U[i]].push_back({V[i], W[i]});
        adj[V[i]].push_back({U[i], W[i]});
    }
    auto bfs = [&](int s) {
        vector<ll> dis(N);
        vector<int> from(N, -1);
        from[s] = s;
        queue<int> q;
        q.push(s);
        while (!q.empty()) {
            int x = q.front();
            q.pop();
            for (auto [y, z] : adj[x]) {
                if (from[y] == -1) {
                    from[y] = x;
                    dis[y] = dis[x] + z;
                    q.push(y);
                }
            }
        }
        return make_pair(dis, from);
    };
    auto [dis_x, from_x] = bfs(X);
    auto [dis_y, from_y] = bfs(Y);
    vector<ll> one(N), two(N);
    for (int i = 0; i < N; i++) {
        tie(one[i], two[i]) = minmax(dis_x[i], dis_y[i]);
    }
    int ans = 0; {
        auto a(one);
        sort(a.begin(), a.end());
        ll sum = 0;
        while (ans < N && sum + a[ans] <= K) sum += a[ans++];
    }
    vector<int> path{X};
    while (path.back() != Y) path.push_back(from_y[path.back()]);
    int M = path.size();
    vector<int> on_path(N);
    for (auto x : path) on_path[x] = 1;
    vector<ll> dp(2 * N + 1, 1e18);
    dp[0] = 0;
    for (int i = 0; i < N; i++) {
        if (!on_path[i]) {
            for (int j = 2 * N; j >= 0; j--) {
                if (j > 0) dp[j] = min(dp[j], dp[j - 1] + one[i]);
                if (j > 1) dp[j] = min(dp[j], dp[j - 2] + two[i]);
            }
        } else {
            for (int j = 2 * N; j >= 0; j--) {
                dp[j] = min(j < 1 ? 1e18 : dp[j - 1] + one[i], j < 2 ? 1e18 : dp[j - 2] + two[i]);
            }
        }
    }
    for (int i = 0; i <= 2 * N; i++) {
        if (dp[i] <= K) ans = max(ans, i);
    }
    return ans;
}

Compilation message (stderr)

closing.cpp: In function 'int max_score(int, int, int, ll, std::vector<int>, std::vector<int>, std::vector<int>)':
closing.cpp:44:9: warning: unused variable 'M' [-Wunused-variable]
   44 |     int M = path.size();
      |         ^

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