Submission #23342

#	Time	Username	Problem	Language	Result	Execution time	Memory
23342		Nurlykhan	Beads and wires (APIO14_beads)	C++14	0 / 100	6 ms	5120 KiB

beads

#include <bits/stdc++.h>
 
#define pii pair<int, int>
#define f first
#define s second
#define pb push_back
#define mp make_pair
#define ll long long 
#define ld long double
#define sz(v) int(v.size())
#define all(v) v.begin(), v.end()
 
using namespace std;
 
const int N = (int) 2e5 + 7;
const int M = (int) 2e6 + 7;
const ll LINF = (ll) 1e16;
const int INF = (int) 1e9 + 7;
const double EPS = (double) 1e-9;
int n;
struct edge {
    int a, b, c;

    edge() {}
};
edge a[N];
ll dp[N][3];
vector<int> v[N];

bool ok(edge x, edge y) {
    if (x.a == y.a || x.a == y.b) return true;
    if (x.b == y.a || x.b == y.b) return true;
    return false;
}

void dfs(int x, int p = -1) {
    for (int mod = 0; mod < 3; mod++) {
        dp[x][mod] = -LINF;
    }
    dp[x][1] = 0;
    for (auto it : v[x]) {
        int go = a[it].a ^ a[it].b ^ x;
        if (go == p) 
            continue;
        dfs(go, x);
        vector<ll> tmp(3);
        for (int mod = 0; mod < 3; mod++) {
            tmp[mod] = dp[x][mod];
        }
        for (int mod = 0; mod < 3; mod++) {
            for (int t = 0; t < 3; t++) {
                tmp[(mod + t) % 3] = max(tmp[(mod + t) % 3], dp[x][mod] + dp[go][t] + a[it].c);
            }
        }
        for (int mod = 0; mod < 3; mod++) {
            dp[x][mod] = tmp[mod];
        }
    }
}
 
int main() {
    #define fn "balls"
    #ifdef witch
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    #else
//        freopen(fn".in", "r", stdin);
//        freopen(fn".out", "w", stdout);
    #endif
    cin >> n;
    for (int i = 0; i < n - 1; i++) {
        cin >> a[i].a >> a[i].b >> a[i].c;
        v[a[i].a].pb(i);
        v[a[i].b].pb(i);
    }
    dfs(1);
    ll ans = 0;
    for (int i = 1; i <= n; i++) {
        ans = max(ans, dp[i][0]);
    }
    cout << ans;
    return 0;
}

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