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답안 #764865

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
764865 2023-06-24T06:04:17 Z The_Samurai Parkovi (COCI22_parkovi) C++17
20 / 110
 113 ms 31904 KB 
#include "bits/stdc++.h"

using namespace std;
using ll = long long;

int n, k;
vector<bool> vis;
vector<vector<pair<int, int>>> g;
vector<ll> dp;
ll ans;
int best_pos;

void sol2_dfs1(int u, int p) {
    for (auto [v, w]: g[u]) {
        if (v == p) {
            continue;
        }
        sol2_dfs1(v, u);
        dp[u] = max(dp[u], dp[v] + w);
    }
}

void sol2_dfs2(int u, int p, ll val) {
    if (ans > max(dp[u], val)) {
        ans = max(dp[u], val);
        best_pos = u;
    }
    ll mx1 = val, mx2 = 0;
    for (auto [v, w]: g[u]) {
        if (v == p) {
            continue;
        }
        if (mx1 < dp[v] + w) {
            mx2 = mx1;
            mx1 = dp[v] + w;
        } else {
            mx2 = max(mx2, dp[v] + w);
        }
    }
    for (auto [v, w]: g[u]) {
        if (v == p) {
            continue;
        }
        if (dp[v] + w == mx1) {
            sol2_dfs2(v, u, mx2 + w);
        } else {
            sol2_dfs2(v, u, mx1 + w);
        }
    }
}

void solve() {
    cin >> n >> k;
    g.assign(n + 1, {});
    for (int i = 1; i < n; i++) {
        int u, v, w;
        cin >> u >> v >> w;
        g[u].emplace_back(v, w);
        g[v].emplace_back(u, w);
    }
    if (k == 1) {
        dp.assign(n + 1, 0);
        ans = 1e18;
        sol2_dfs1(1, 0);
        sol2_dfs2(1, 0, 0);
        cout << ans << '\n' << best_pos;
        return;
    }
    if (n <= 20) {
        ans = 1e18;
        vector<int> built;
        for (int i = 0; i < (1 << n); i++) {
            if (__builtin_popcount(i) != k) {
                continue;
            }
            priority_queue<pair<ll, int>> pq;
            vector<int> now;
            for (int j = 0; j < n; j++) {
                if ((1 << j) & i) {
                    pq.emplace(0, j + 1);
                    now.emplace_back(j + 1);
                }
            }
            vis.assign(n + 1, false);
            ll close = 0;
            while (!pq.empty()) {
                auto [d1, u] = pq.top();
                pq.pop();
                if (vis[u]) {
                    continue;
                }
                vis[u] = true;
                d1 = -d1;
                close = max(close, d1);
                for (auto [v, d2]: g[u]) {
                    if (!vis[v]) {
                        pq.emplace(-d1 - d2, v);
                    }
                }
            }
            if (ans > close) {
                ans = close;
                built = now;
            }
        }
        cout << ans << '\n';
        for (int x: built) {
            cout << x << ' ';
        }
        return;
    }

}

int main() {
    ios_base::sync_with_stdio(false);
    cout.tie(nullptr);
    cin.tie(nullptr);

    int queries = 1;
#ifdef test_cases
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
//    cin >> queries;
#else
    //    cin >> queries;
#endif

    for (int test_case = 1; test_case <= queries; test_case++) {
        solve();
//        cout << '\n';
    }
}

Subtask #1
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 212 KB Output is correct
2 Correct 4 ms 320 KB Output is correct
3 Correct 4 ms 320 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 4 ms 312 KB Output is correct
6 Correct 17 ms 212 KB Output is correct
7 Correct 18 ms 212 KB Output is correct
8 Correct 8 ms 212 KB Output is correct
9 Correct 77 ms 212 KB Output is correct
10 Correct 8 ms 212 KB Output is correct
11 Correct 52 ms 312 KB Output is correct
12 Correct 87 ms 296 KB Output is correct
13 Correct 4 ms 320 KB Output is correct
14 Correct 38 ms 296 KB Output is correct

Subtask #2
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 55 ms 26636 KB Output is correct
2 Correct 78 ms 31904 KB Output is correct
3 Correct 65 ms 18748 KB Output is correct
4 Correct 113 ms 17344 KB Output is correct
5 Correct 87 ms 16844 KB Output is correct
6 Correct 73 ms 16716 KB Output is correct
7 Correct 67 ms 15528 KB Output is correct
8 Correct 84 ms 16504 KB Output is correct
9 Correct 79 ms 16740 KB Output is correct
10 Correct 74 ms 17036 KB Output is correct
11 Correct 77 ms 18564 KB Output is correct
12 Correct 70 ms 18312 KB Output is correct
13 Correct 81 ms 20020 KB Output is correct
14 Correct 69 ms 16988 KB Output is correct
15 Correct 60 ms 16460 KB Output is correct
16 Correct 72 ms 17928 KB Output is correct
17 Correct 66 ms 17132 KB Output is correct

Subtask #3
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 52 ms 10968 KB Unexpected end of file - int64 expected
2 Halted 0 ms 0 KB -

Subtask #4
0 / 60.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 212 KB Output is correct
2 Correct 4 ms 320 KB Output is correct
3 Correct 4 ms 320 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 4 ms 312 KB Output is correct
6 Correct 17 ms 212 KB Output is correct
7 Correct 18 ms 212 KB Output is correct
8 Correct 8 ms 212 KB Output is correct
9 Correct 77 ms 212 KB Output is correct
10 Correct 8 ms 212 KB Output is correct
11 Correct 52 ms 312 KB Output is correct
12 Correct 87 ms 296 KB Output is correct
13 Correct 4 ms 320 KB Output is correct
14 Correct 38 ms 296 KB Output is correct
15 Correct 55 ms 26636 KB Output is correct
16 Correct 78 ms 31904 KB Output is correct
17 Correct 65 ms 18748 KB Output is correct
18 Correct 113 ms 17344 KB Output is correct
19 Correct 87 ms 16844 KB Output is correct
20 Correct 73 ms 16716 KB Output is correct
21 Correct 67 ms 15528 KB Output is correct
22 Correct 84 ms 16504 KB Output is correct
23 Correct 79 ms 16740 KB Output is correct
24 Correct 74 ms 17036 KB Output is correct
25 Correct 77 ms 18564 KB Output is correct
26 Correct 70 ms 18312 KB Output is correct
27 Correct 81 ms 20020 KB Output is correct
28 Correct 69 ms 16988 KB Output is correct
29 Correct 60 ms 16460 KB Output is correct
30 Correct 72 ms 17928 KB Output is correct
31 Correct 66 ms 17132 KB Output is correct
32 Incorrect 52 ms 10968 KB Unexpected end of file - int64 expected
33 Halted 0 ms 0 KB -