Submission #1057499

#	Time	Username	Problem	Language	Result	Execution time	Memory
1057499		mychecksedad	Radio Towers (IOI22_towers)	C++17	100 / 100	915 ms	64996 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
const int N = 300005, K = 20;

struct Node{
  Node *L, *R;
  int sum, mostleft, mostright;
  Node(){
    L=R=nullptr;
    sum=0;
    mostleft=mostright=0;
  }
  Node(Node*l, Node*r): L(l), R(r){
    sum = 0;
    mostleft = 100000000;
    mostright = -1;
    if(l != nullptr) sum += l->sum, mostleft = min(mostleft, l->mostleft), mostright = max(mostright, l->mostright);
    if(r != nullptr) sum += r->sum, mostleft = min(mostleft, r->mostleft), mostright = max(mostright, r->mostright);
  }
  Node(int s, int pos): sum(s){
    if(s == 1)
      mostleft = mostright = pos;
    else 
      mostleft = 100000000, mostright = -1;
    L=R=nullptr;
  }
};
vector<bool> is_peak(300005);

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

array<int, 3> get(Node *v, int l, int r, int ql, int qr){
  if(ql > r || l > qr) return {0, 100000000, -1};
  if(ql <= l && r <= qr){
    return {v->sum, v->mostleft, v->mostright};
  }
  int m = l+r>>1;

  auto x = get(v->L, l, m, ql, qr);
  auto y = get(v->R, m+1, r, ql, qr);
  return {x[0] + y[0], min(x[1], y[1]), max(x[2], y[2])};
}
int rmq[N][K];
int getmin(int l, int r){
  int k = int(log2(r-l+1));
  return min(rmq[l][k], rmq[r-(1<<k)+1][k]);
}

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;
vector<pair<int, Node*>> roots;
void init(int nn, vector<int> aa) { n=nn;a=aa;
  if(n == 1) return;
  op(a, A, B);

  for(int i = 0; i < n; ++i) rmq[i][0] = a[i];
  for(int j = 1; j < K; ++j){
    for(int i = 0; i + (1<<j) <= n; ++i){
      rmq[i][j] = min(rmq[i][j - 1], rmq[i + (1<<(j-1))][j - 1]);
    }
  }

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

  int m = A.size();
  for(int i = 0; i < m; ++i){
    S.insert({i, A[i], B[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});
  }
  roots.pb({0, build(0, n - 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], B[v]});
    S.erase({u, A[u], B[u]});
    rem[u] = rem[v] = 1;
    int mx = max(u, v);
    auto it = S.lower_bound(array<int,3>{mx, -1, -1});
    if(it != S.begin() && it != S.end()){
      auto it2 = prev(it);
      auto x = *it;
      auto y = *it2;
      Q.push({-abs(x[1] - y[1]), x[0], y[0]});
    }
    if(ans.back().ff == -val){
      roots.back().ss = upd(roots.back().ss, 0, n - 1, (A[v] > A[u] ? B[v] : B[u]), 0);
      ans.back().ss = S.size() / 2 + 1;
    }else{
      roots.pb({-val, upd(roots.back().ss, 0, n - 1, (A[v] > A[u] ? B[v] : B[u]), 0)});
      ans.pb({-val, S.size() / 2 + 1});
    }
  }

}

int max_towers(int L, int R, int D) {
  if(n == 1 || L == R || A.size() == 1) return 1;
  int pos = upper_bound(all(ans), pii{D, -1}) - ans.begin() - 1;
  if(pos == ans.size()) return 1;
  auto F = get(roots[pos].ss, 0, n - 1, L, R);
  int l = F[1], r = F[2], cur = F[0];
  if(cur == 0) return 1;
  if(L < l){
    cur += getmin(L, l-1) <= a[F[1]] - D;
  }
  if(r < R){
    cur += getmin(r + 1, R) <= a[F[2]] - D;
  }
  return max(1, cur - 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:43:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   43 |   int m = l+r>>1;
      |           ~^~
towers.cpp: In function 'Node* upd(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 'std::array<int, 3> get(Node*, int, int, int, int)':
towers.cpp:61:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   61 |   int m = l+r>>1;
      |           ~^~
towers.cpp: In function 'void op(std::vector<int>&, std::vector<int>&, std::vector<int>&)':
towers.cpp:83:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   83 |   for(int i = 2; i < a.size(); ++i){
      |                  ~~^~~~~~~~~~
towers.cpp: In function 'int max_towers(int, int, int)':
towers.cpp:167:10: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  167 |   if(pos == ans.size()) return 1;
      |      ~~~~^~~~~~~~~~~~~

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