Submission #546228

#	Time	Username	Problem	Language	Result	Execution time	Memory
546228		Ooops_sorry	Beads and wires (APIO14_beads)	C++14	0 / 100	4 ms	5036 KiB

beads

#include<bits/stdc++.h>

using namespace std;

#define int long long
#define pb push_back
#define ld double
#define ll __int128

mt19937 rnd(51);

const int N = 2e5 + 10, INF = 1e18;
vector<pair<int,int>> g[N];
int res[N][2];

void dfs(int v, int p) {
    vector<int> dp(3, -INF);
    dp[0] = 0;
    for (auto [to, c] : g[v]) {
        if (to != p) {
            dfs(to, v);
            vector<int> dpp(3);
            for (int j = 0; j < 2; j++) {
                dpp[j + 1] = max(dpp[j + 1], dp[j] + res[to][0] + c);
            }
            for (int j = 0; j < 3; j++) {
                dpp[j] = max(dpp[j], dp[j] + max(res[to][1] + c, res[to][0]));
            }
            swap(dp, dpp);
        }
    }
    res[v][0] = max(dp[0], dp[2]);
    res[v][1] = dp[1];
}

signed main() {
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
#endif // LOCAL
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n;
    cin >> n;
    for (int i = 0; i < n - 1; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        a--, b--;
        g[a].pb({b, c});
        g[b].pb({a, c});
    }
    dfs(0, -1);
    cout << res[0][0] << endl;
    return 0;
}

Compilation message (stderr)

beads.cpp: In function 'void dfs(long long int, long long int)':
beads.cpp:19:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   19 |     for (auto [to, c] : g[v]) {
      |               ^

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