Submission #1057451

#	Time	Username	Problem	Language	Result	Execution time	Memory
1057451		mychecksedad	Radio Towers (IOI22_towers)	C++17	17 / 100	656 ms	9196 KiB

towers

#include "towers.h"
#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define all(x) x.begin(),x.end()
#define ll long long int
#define en cout << '\n'
#define pii pair<int,int>
#define vi vector<int> 
#define ff first
#define ss second

struct Node{
  Node *L, *R;
  int sum;
  Node(){
    L=R=nullptr;
    sum=0;
  }
  Node(Node*l, Node*r): L(l), R(r){
    sum = 0;
    if(l != nullptr) sum += l->sum;
    if(r != nullptr) sum += r->sum;
  }
  Node(int s): sum(s){
    L=R=nullptr;
  }
};
vector<bool> is_peak(300005);

Node *build(int l, int r){
  if(l == r){
    return new Node(is_peak[l]);
  }
  int m = l+r>>1;
  return new Node(build(l, m), build(m+1, r));
}

Node *upd(Node *v, int l, int r, int p, int val){
  if(l == r){
    return new Node(val);
  }
  int m = l+r>>1;
  if(p <= m) return new Node(upd(v->L, l, m, p, val), v->R);
  return new Node(v->L, upd(v->R, m+1, r, p, val));
}

int get(Node *vl, Node *vr, int l, int r, int ql, int qr){
  if(ql > r || l > qr) return 0;
  if(ql <= l && r <= qr) return vr->sum - vl->sum;
  int m = l+r>>1;
  return get(vl->L, vr->L, l, m, ql, qr) + get(vl->R, vr->R, m+1, r, ql, qr);
}

void op(vector<int> &a, vector<int> &A, vector<int> &B){
  if(a.size() <= 1){
    A = a;
    B.pb(0);
    return;
  }
  A.pb(a[0]);
  A.pb(a[1]);
  B.pb(0);
  B.pb(1);
  for(int i = 2; i < a.size(); ++i){
    if(a[i] > A.back() && A.back() > A[int(A.size()) - 2]){
      A.pop_back();
      B.pop_back();
      A.pb(a[i]);
      B.pb(i);
    }else if(a[i] < A.back() && A.back() < A[int(A.size()) - 2]){
      A.pop_back();
      B.pop_back();
      A.pb(a[i]);
      B.pb(i);
    }else{
      A.pb(a[i]);
      B.pb(i);
    }
  }
  
}
int n;
vector<int> A, B, a;
vector<pair<int, int>> ans;
void init(int nn, std::vector<int> aa) { n=nn;a=aa;
  if(n == 1) return;
  op(a, A, B);


  if(A[0] > A[1]) A.erase(A.begin()), B.erase(B.begin());
  if(A.size()==1) return;
  if(A.back() > A[A.size() - 2]) A.pop_back(), B.pop_back();
  if(A.size()==1) return;

  set<pair<int,int>> S;
  priority_queue<array<int, 3>> Q;

  int m = A.size();
  for(int i = 0; i < m; ++i){
    S.insert({i, A[i]});
    if(i%2) is_peak[B[i]] = 1;
    if(i + 1 < m && A[i + 1] > A[i]) Q.push({-(A[i + 1] - A[i]), i, i + 1});
    if(i > 0 && A[i - 1] > A[i]) Q.push({-(A[i - 1] - A[i]), i, i - 1});
  }
  vector<pair<int, Node*>> roots;
  // roots.pb({1, });

  ans.pb({0, A.size() / 2 + 1});
  vector<bool> rem(A.size());
  while(!Q.empty()){
    auto V = Q.top();
    int v = V[1], u = V[2];
    int val = V[0];
    Q.pop();
    if(rem[u] || rem[v]) continue;
    S.erase({v, A[v]});
    S.erase({u, A[u]});
    rem[u] = rem[v] = 1;
    int mx = max(u, v);
    auto it = S.lower_bound(pair<int,int>{mx, -1});
    if(it != S.begin() && it != S.end()){
      auto it2 = prev(it);
      auto x = *it;
      auto y = *it2;
      Q.push({-abs(x.ss - y.ss), x.ff, y.ff});
    }
    // assert(S.size()%2);
    if(ans.back().ff == -val){
      ans.back().ss = S.size() / 2 + 1;
    }else ans.pb({-val, S.size() / 2 + 1});
  }

}

int max_towers(int L, int R, int D) { ++L, ++R;
  if(n == 1 || L == R || A.size() == 1) return 1;
  int pos = upper_bound(all(ans), pii{D, -1}) - ans.begin() - 1;
  // if(D==1) return ans[0].ss;
  return max(pos == ans.size() ? 1 : ans[pos].ss, 1);
}

Compilation message (stderr)

towers.cpp: In function 'Node* build(int, int)':
towers.cpp:35:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   35 |   int m = l+r>>1;
      |           ~^~
towers.cpp: In function 'Node* upd(Node*, int, int, int, int)':
towers.cpp:43:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   43 |   int m = l+r>>1;
      |           ~^~
towers.cpp: In function 'int get(Node*, Node*, int, int, int, int)':
towers.cpp:51:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   51 |   int m = l+r>>1;
      |           ~^~
towers.cpp: In function 'void op(std::vector<int>&, std::vector<int>&, std::vector<int>&)':
towers.cpp:65:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   65 |   for(int i = 2; i < a.size(); ++i){
      |                  ~~^~~~~~~~~~
towers.cpp: In function 'int max_towers(int, int, int)':
towers.cpp:140:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  140 |   return max(pos == ans.size() ? 1 : ans[pos].ss, 1);
      |              ~~~~^~~~~~~~~~~~~

• Subtask 1: 0 / 4
• Subtask 2: 0 / 11
• Subtask 3: 0 / 12
• Subtask 4: 0 / 14
• Subtask 5: 17 / 17
• Subtask 6: 0 / 19
• Subtask 7: 0 / 23