Submission #249113

#	Time	Username	Problem	Language	Result	Execution time	Memory
249113		receed	Beads and wires (APIO14_beads)	C++14	28 / 100	1091 ms	5760 KiB

beads

#include <iostream>
#include <iomanip>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cstring>
#include <cassert>
#include <string>
#include <set>
#include <map>
#include <random>
#include <bitset>
#include <string>
#include <unordered_set>
#include <unordered_map>
#include <deque>
#include <queue>
#define rep(i, n) for (int i = 0; i < (n); i++)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
 
using namespace std;
using ll = long long;
using ul = unsigned long long;
using ld = long double;
 
const int N = 200001;
vector<pair<int, int>> g[N];
ll d0[N], d1[N], inf = 1e11;
 
void dfs(int v, int p) {
    d0[v] = 0;
    ll m1 = -inf, m2 = -inf, cm;
    for (auto &e : g[v]) {
        if (e.first == p)
            continue;
        dfs(e.first, v);
        ll cx = max(d0[e.first], d1[e.first] + e.second);
        d0[v] += cx;
        cm = d0[e.first] - cx + e.second;
        if (cm > m1) {
            m2 = m1;
            m1 = cm;
        }
        else if (cm > m2)
            m2 = cm;
    }
    d1[v] = d0[v] + m1;
}
 
int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    int n, u, v, w;
    cin >> n;
    rep(i, n - 1) {
        cin >> u >> v >> w;
        u--; v--;
        g[u].push_back({v, w});
        g[v].push_back({u, w});
    }
    ll ans = 0;
    rep(i, n) {
        dfs(i, -1);
        ans = max(ans, d0[i]);
    }
    cout << ans;
}

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