Submission #997270

#	Time	Username	Problem	Language	Result	Execution time	Memory
997270		biank	Closing Time (IOI23_closing)	C++17	0 / 100	39 ms	13472 KiB

closing

#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using ii = pair<int, int>;

const ll INF = 1e18;
const int MAX_N = 3000;

vector<ii> adj[MAX_N];

void dfs(int u, vector<ll> &dist, int p = -1, ll d = 0) {
    dist[u] = d;
    for (auto [v, w] : adj[u]) {
        if (v != p) dfs(v, dist, u, d + w);
    }
}

int max_score(int N, int X, int Y, ll K, vector<int> U, vector<int> V, vector<int> W) {
    for (int i = 0; i < N; i++) adj[i].clear(); 
    for (int i = 0; i < N - 1; i++) {
        adj[U[i]].emplace_back(V[i], W[i]);
        adj[V[i]].emplace_back(U[i], W[i]);
    }
    vector<ll> distToX(N), distToY(N);
    dfs(X, distToX), dfs(Y, distToY);
    vector<ll> val[2], pref[2];
    for (int i = 0; i < 2; i++) {
        val[i].resize(N);
        pref[i].assign(N + 1, 0);
    }
    for (int i = 0; i < N; i++) {
        tie(val[0][i], val[1][i]) = minmax(distToX[i], distToY[i]);
        val[1][i] -= val[0][i];
        for (int j = 0; j < 2; j++) {
            pref[j][i + 1] = pref[j][i] + val[j][i];
        }
    }
    int ans = 0;
    for (int i = 0; i < N; i++) {
        for (int j = min(i, X); j < N; j++) {
            for (int k = 0; k <= Y; k++) {
                int l = Y - 1, r = N;
                while (l + 1 < r) {
                    int m = (l + r) / 2;
                    ll sum;
                    if (j < k) {
                        sum = pref[0][m + 1] - pref[0][k] + pref[0][j + 1] - pref[0][i];
                    } else {
                        sum = pref[0][m + 1] - pref[0][min(i, k)] + pref[1][j + 1] - pref[1][max(k, i)];
                    }
                    if (sum <= K) l = m;
                    else r = m;
                }
                if (l != Y - 1) {
                    ans = max(ans, j - i + 1 + l - k + 1);
                }
            }
        }
    }
    return ans;
}

• Subtask 0: 0 / 0
• Subtask 1: 0 / 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