제출 #970650

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
970650		GrindMachine	구슬과 끈 (APIO14_beads)	C++17	0 / 100	2 ms	5980 KiB

beads

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a,b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a,b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*



*/

const int MOD = 1e9 + 7;
const int N = 2e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

vector<pll> adj[N];
ll dp[N][2];

void dfs1(ll u, ll p, ll pw){
    for(auto [v,w] : adj[u]){
        if(v == p) conts;
        dfs1(v,u,w);
    }

    // dont pick incoming
    ll curr_dp[3], nxt_dp[3];
    memset(curr_dp,-0x3f,sizeof curr_dp);
    memset(nxt_dp,-0x3f,sizeof nxt_dp);
    curr_dp[0] = 0;

    for(auto [v,w] : adj[u]){
        if(v == p) conts;
        rep(j,3){
            amax(nxt_dp[j], curr_dp[j]+max(dp[v][0],dp[v][1]));
            if(j+1 < 3){
                amax(nxt_dp[j+1], curr_dp[j]+w+dp[v][0]);
            }
        }

        rep(j,3){
            curr_dp[j] = nxt_dp[j];
            nxt_dp[j] = -inf2;
        }
    }

    dp[u][0] = max(curr_dp[0],curr_dp[2]);

    // pick incoming
    memset(curr_dp,-0x3f,sizeof curr_dp);
    memset(nxt_dp,-0x3f,sizeof nxt_dp);
    curr_dp[1] = pw;

    for(auto [v,w] : adj[u]){
        if(v == p) conts;
        rep(j,3){
            amax(nxt_dp[j], curr_dp[j]+max(dp[v][0],dp[v][1]));
            if(j+1 < 3){
                amax(nxt_dp[j+1], curr_dp[j]+w+dp[v][0]);
            }
        }

        rep(j,3){
            curr_dp[j] = nxt_dp[j];
            nxt_dp[j] = -inf2;
        }
    }

    dp[u][1] = curr_dp[2];
}

void solve(int test_case)
{
    ll n; cin >> n;
    rep1(i,n-1){
        ll u,v,w; cin >> u >> v >> w;
        adj[u].pb({v,w}), adj[v].pb({u,w});
    }

    dfs1(1,-1,0);
    ll ans = dp[1][0];
    cout << ans << endl;
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;

    rep1(i, t) {
        solve(i);
    }

    return 0;
}

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