Submission #549481

#	Time	Username	Problem	Language	Result	Execution time	Memory
549481		farhan132	Beads and wires (APIO14_beads)	C++17	100 / 100	259 ms	43520 KiB

beads

/***Farhan132***/
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma")
//#pragma GCC optimization ("unroll-loops")
//#pragma GCC optimize("Ofast,fast-math")
 
 
#include <bits/stdc++.h>
 
 
 
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
typedef double dd;
typedef vector<ll> vll;
typedef pair<ll , ll> ii;
typedef vector< ii > vii;
typedef pair < pair < ll , ll > , pair < ll , ll > > cm; 
typedef tuple < ll,  ll, ll > tp;
 
#define ff first
#define ss second
#define pb push_back
#define in insert
#define f0(b) for(int i=0;i<(b);i++)
#define f00(b) for(int j=0;j<(b);j++)
#define f1(b) for(int i=1;i<=(b);i++)
#define f11(b) for(int j=1;j<=(b);j++)
#define f2(a,b) for(int i=(a);i<=(b);i++)
#define f22(a,b) for(int j=(a);j<=(b);j++)
#define sf(a) scanf("%lld",&a)
#define sff(a,b) scanf("%lld %lld", &a , &b)
#define pf(a) printf("%lld\n",a)
#define pff(a,b) printf("%lld %lld\n", a , b)
#define bug printf("**!\n")
#define mem(a , b) memset(a, b ,sizeof(a))
#define front_zero(n) __builtin_clzll(n)
#define back_zero(n) __builtin_ctzll(n)
#define total_one(n) __builtin_popcount(n)
#define clean fflush(stdout)
 
const ll mod =  (ll) 998244353;
//const ll mod =  (ll) 1e9 + 7;
const ll maxn = (ll)1e8 + 5;
const int nnn = 1048590;
const int inf = numeric_limits<int>::max()-1;
//const ll INF = numeric_limits<ll>::max()-1;
const ll INF = (ll)1e18;
 
ll dx[]={0,1,0,-1};
ll dy[]={1,0,-1,0};
ll dxx[]={0,1,0,-1,1,1,-1,-1};
ll dyy[]={1,0,-1,0,1,-1,1,-1};
 
bool USACO = 0;
 
mt19937 rng(chrono::system_clock::now().time_since_epoch().count());
 
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
 
template <typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

const ll N = 2e5 + 5;

ll dp[N][4];
vector < ii > v[N];

void dfs(ll s, ll p, ll e){

    dp[s][0] = 0;
    dp[s][1] = -1e18;
    dp[s][2] = -1e18;
    dp[s][3] = -1e18;
    vector < tuple < ll, ll , ll, ll, ll > > g;
    ll sum = 0, s2 = 0;
    multiset < ll > m;
    for(auto [u, w] : v[s]){
        if(u - p){
            dfs(u, s, w);
            dp[s][0] += max({dp[u][0], dp[u][1]});
            sum += max({dp[u][0], dp[u][1]});
            s2 += max({dp[u][0], dp[u][1], dp[u][3]});
            g.pb({dp[u][0], dp[u][1], dp[u][2], dp[u][3], w});

        }
    }
    vector < ll > benefit;

    for(auto [x, y, z, c, w]: g){
        m.in((x + w) - max({x, y}));
    }
    //dp[s][2] = sum;
    for(auto [x, y, z, c, w] : g){
        sum -= max({x, y});
        s2 -= max({x, y, c});
        dp[s][1] = max(dp[s][1], sum + e + w + x);
        dp[s][3] = max(dp[s][3], sum + e + w + z);
        ll k = (x + w) - max({x, y});
        m.erase(m.find(k));
        if(m.size()){
            dp[s][2] = max({dp[s][2] , sum + (max(x, z) + w) + *(m.rbegin())});
        }
        dp[s][2] = max({dp[s][2], sum + max(z, c)});
        m.in(k);
        sum += max({x, y});
        s2 += max({x, y, c});
    }
    sort(benefit.begin(), benefit.end(),[](ll a, ll b){
        return a > b;
    });

    return;
}

void solve(){
  
  ll n; cin >> n;

  for(ll i = 1; i < n; i++){
    ll x, y, w; cin >> x >> y >> w;
    v[x].pb({y, w});
    v[y].pb({x, w});
  } 

  dfs(1, 0, 0);

  cout << max(dp[1][0],dp[1][2]) << '\n';

   
  return;
}
 
int main() {
    
    
    #ifdef LOCAL
        freopen("in", "r", stdin);
        freopen("out", "w", stdout);
        auto start_time = clock();
    #else 
       ios_base::sync_with_stdio(0); cin.tie(NULL); cout.tie(NULL);
    #endif
 
    //pre(N);
 
    ll T = 1, CT = 0;  //cin >> T; 
 
    while(T--){
       //  cout << "Case #" << ++CT <<": " ;
        solve();
    }
    #ifdef LOCAL
        auto end_time = clock();
        cerr<< "Execution time: "<<(end_time - start_time)*(int)1e3/CLOCKS_PER_SEC<<" ms\n";
    #endif
 
    return 0;
}

Compilation message (stderr)

beads.cpp: In function 'int main()':
beads.cpp:150:15: warning: unused variable 'CT' [-Wunused-variable]
  150 |     ll T = 1, CT = 0;  //cin >> T;
      |               ^~

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