Submission #374950

#	Time	Username	Problem	Language	Result	Execution time	Memory
374950		valerikk	Beads and wires (APIO14_beads)	C++17	0 / 100	4 ms	364 KiB

beads

#include <bits/stdc++.h>

using namespace std;

int main() {
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
#endif
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    vector<int> a(n), b(n), c(n);
    for (int i = 0; i < n - 1; ++i) {
        cin >> a[i] >> b[i] >> c[i];
        --a[i];
        --b[i];
    }
    int ans = 0;
    vector<pair<int, int>> pairs;
    function<void()> go = [&]() {
        vector<int> cnt_center(n, 0);
        for (auto p : pairs) {
            int i = p.first, j = p.second;
            map<int, int> mp;
            ++mp[a[i]]; ++mp[b[i]];
            ++mp[a[j]]; ++mp[b[j]];
            for (auto [v, cnt] : mp) {
                if (cnt >= 2) ++cnt_center[v];
            }
        }
        bool ok = 1;
        for (int i = 0; i < n; ++i) ok &= cnt_center[i] <= 1;
        if (ok) {
            int cur_ans = 0;
            vector<bool> used(n, 0);
            for (auto p : pairs) {
                used[p.first] = used[p.second] = 1;
                cur_ans += c[p.first];
                cur_ans += c[p.second];
            }
            ans = max(ans, cur_ans);
            for (int i = 0; i < n - 1; ++i) {
                for (int j = i + 1; j < n - 1; ++j) {
                    map<int, int> mp;
                    ++mp[a[i]]; ++mp[b[i]];
                    ++mp[a[j]]; ++mp[b[j]];
                    bool can = 0;
                    for (auto [v, cnt] : mp) {
                        if (cnt >= 2) can = 1;
                    }
                    if (can && !used[i] && !used[j]) {
                        pairs.push_back({i, j});
                        go();
                        pairs.pop_back();
                    }
                }
            }
        }
    };
    go();
    cout << ans << endl;
    return 0;
}

• Subtask 1: 0 / 13
• Subtask 2: 0 / 15
• Subtask 3: 0 / 29
• Subtask 4: 0 / 43