Submission #1225362

#	Time	Username	Problem	Language	Result	Execution time	Memory
1225362		mychecksedad	Construction of Highway (JOI18_construction)	C++20	100 / 100	257 ms	88768 KiB

construction

/* Author : Mychecksdead  */
#include<bits/stdc++.h>
using namespace std;
#define ll long long int
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define pb push_back
#define all(x) x.begin(), x.end()
#define en cout << '\n'
#define ff first
#define ss second
#define pii pair<int,int>
#define vi vector<int>
const int N = 1e6+100, M = 1e5+10, K = 52, MX = 30;


struct Fenwick{
  int n;
  vector<int> t;
  Fenwick(int _n){
    n = _n;
    t.resize(n+1, 0);
  }
  void add(int v, int val){
    while(v <= n){
      t[v]+=val;
      v += (v&-v);
    }
  }
  ll get(int v){
    ll res = 0;
    while(v > 0){
      res += t[v];
      v -= (v&-v);
    }
    return res;
  }
};
 

int n, c[N], par[N], tin[N], heavy[N], sz[N], timer = 1, tout[N];
vector<array<int, 2>> a;
vi g[N];
set<pii> S[N];
Fenwick fw(N);
void pre(int v){
  sz[v] = 1;
  for(int &u: g[v]){
    pre(u);
    sz[v] += sz[u];
    if(sz[u] > sz[g[v][0]]) swap(g[v][0], u);
  }
}
void dfs(int v){
  tin[v] = timer++;
  for(int u: g[v]){
    par[u] = v;
    if(u == g[v][0]) heavy[u] = heavy[v];
    else heavy[u] = u;
    dfs(u);
  }
  tout[v] = timer - 1;
}

void add(int v, int val){
  // begin at v, go up, while doing it add {tin[v], val}
  while(true){
    int t = heavy[v];
    while(S[t].size() && (*S[t].begin()).ff <= tin[v]){
      S[t].erase(S[t].begin());
    }
    if(S[t].empty() || (*S[t].begin()).ss != val){
      S[t].insert({tin[v], val});
    }
    if(heavy[v] == 1) break;
    v = par[heavy[v]];
  }
}

ll calc(int v){
  ll res = 0;
  // begin at v, while going up calculate via fenwick
  vector<pii> used;
  // cerr << v << " her\n";
  int vv = v;
  while(true){
    int t = heavy[v];
    auto it = S[t].lower_bound(pii{tin[v] - (v == vv), -1});
    // cerr << v << '\n';
    // for(auto [x, y]: S[t]) cerr << x << ' ' << y << ',';
    //   cerr << '\n';
    //   cerr << '\n';

    if(S[t].size()){
      if(it == S[t].end()) --it;
      int cur = tin[v] - (vv == v);
      while(true){
        int nxt = (it == S[t].begin() ? tin[heavy[v]] - 1 : (*prev(it)).ff);
        int cnt = cur - nxt;
        used.pb({(*it).ss, cnt});
        res += fw.get((*it).ss - 1) * cnt;
        fw.add((*it).ss, cnt);
        if(it == S[t].begin()) break;
        --it;
        cur = nxt;
      }
    }

    if(heavy[v] == 1) break;
    v = par[heavy[v]];
  }


  for(auto [x, y]: used) fw.add(x, -y);
  return res;
}

void solve(){
  cin >> n;
  vi val;
  for(int i = 1; i <= n; ++i){
    cin >> c[i];
    val.pb(c[i]);
  }
  for(int i = 1; i < n; ++i){
    int u, v; cin >> u >> v;
    a.pb({u, v});
    g[u].pb(v);
  }
  sort(all(val));
  for(int i = 1; i <= n; ++i){
    c[i] = lower_bound(all(val), c[i]) - val.begin() + 1;
  }

  pre(1);
  heavy[1] = 1;
  dfs(1);

  add(1, c[1]);

  for(auto [u, v]: a){
    cout << calc(v) << '\n';
    add(v, c[v]);
  }
}


int main(){
  cin.tie(0); ios::sync_with_stdio(0);
  int tt = 1, aa;
  // freopen("in.txt", "r", stdin);
  // freopen("out.txt", "w", stdout);
  while(tt--){
    solve();
    en;
  }
  cerr<<"time taken : "<<(float)clock()/CLOCKS_PER_SEC<<" seconds\n";
  return 0;
} 

• Subtask 1: 7 / 7
• Subtask 2: 9 / 9
• Subtask 3: 84 / 84