Submission #1070609

#	Time	Username	Problem	Language	Result	Execution time	Memory
1070609		Boas	Radio Towers (IOI22_towers)	C++17	23 / 100	4094 ms	6344 KiB

towers

#include "towers.h"

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;

template <typename T1, typename T2>
using indexed_map = tree<T1, T2, less<T1>, rb_tree_tag, tree_order_statistics_node_update>;
template <typename T>
using indexed_set = indexed_map<T, null_type>;

#define loop(x, i) for (int i = 0; i < (x); i++)
#define loop1(x, i) for (int i = 1; i <= (x); i++)
#define rev(x, i) for (int i = (int)(x) - 1; i >= 0; i--)
#define itloop(x) for (auto it = begin(x); x != end(x); it++)
#define itrev(x) for (auto it = rbegin(x); x != rend(x); it++)
#define INF ((int64_t)(4e18 + 1))
#define INF32 ((int32_t)(2e9 + 1))
#define ALL(x) begin(x), end(x)
#define RALL(x) rbegin(x), rend(x)
#define removeIn(x, l) l.erase(find(ALL(l), x))
#define pb push_back
#define sz(x) (int)(x).size()
#define F first
#define S second
#define var const auto &
#define foreach(l) for (var e : l)

typedef int8_t i8;
typedef int16_t i16;
typedef int32_t i32;
typedef int64_t i64;
typedef pair<int, int> ii;
typedef tuple<int, int, int> iii;
typedef tuple<int, int, int, int> iiii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ii> vii;
typedef vector<iii> viii;
typedef vector<vii> vvii;
typedef vector<viii> vviii;
typedef set<int> si;
typedef set<ii> sii;
typedef set<iii> siii;
typedef vector<si> vsi;
typedef vector<sii> vsii;
typedef vector<vsi> vvsi;
typedef vector<string> vstr;
typedef vector<vector<string>> vvstr;
typedef vector<bool> vb;
typedef vector<vb> vvb;

vi h;
vii minTree, maxTree;
int n;
int treeN = 1;

void init(int N, vi H)
{
  h = H;
  n = N;
  while (treeN < N)
    treeN *= 2;
  minTree = vii(treeN * 2, {1e9, 1e9});
  maxTree = vii(treeN * 2, {0, -1e9});
  loop(n, i)
  {
    minTree[treeN + i] = {H[i], i};
    maxTree[treeN + i] = {H[i], -i};
  }
  rev(treeN, i)
  {
    minTree[i] = min(minTree[2 * i + 1], minTree[2 * i]);
    maxTree[i] = max(maxTree[2 * i + 1], maxTree[2 * i]);
  }
}

ii combine(ii a, ii b, bool minOp)
{
  if (minOp)
    return min(a, b);
  return max(a, b);
}

// v, ix
ii query(int i, int l, int r, int ql, int qr, bool minOp)
{
  if (r < ql || qr < l)
    return {1e9 * minOp, 1e9 * minOp};
  int m = l + (r - l) / 2;
  if (ql <= l && r <= qr)
  {
    if (minOp)
      return minTree[i];
    return maxTree[i];
  }
  return combine(query(2 * i, l, m, ql, qr, minOp),
                 query(2 * i + 1, m + 1, r, ql, qr, minOp), minOp);
}

int max_towers(int L, int R, int D)
{
  vi dp(R + 1, 1);
  vi maxDP(R + 1, 1);
  for (int i = R - 2; i >= L; i--)
  {
    int lo = i + 2, hi = R;
    bool suc = 0;
    int lastIx = -1;
    while (hi >= lo)
    {
      int m = lo + (hi - lo) / 2;
      if (i + 1 > m - 1)
      {
        lo = m + 1;
        continue;
      }
      auto [mn, mnIx] = query(1, 0, treeN - 1, i + 2, m, 1);
      auto [mx, mxIx] = query(1, 0, treeN - 1, i + 1, mnIx - 1, 0);
      mxIx *= -1;
      if (mx - max(mn, h[i]) >= D)
      {
        lastIx = mnIx;
        suc = 1;
        if (lo == hi)
          break;
        hi = m;
      }
      else
      {
        lo = m + 1;
      }
    }
    if (suc)
    {
      dp[i] = maxDP[lastIx] + 1;
    }
    maxDP[i] = max(dp[i], maxDP[i + 1]);
  }
  return *max_element(ALL(dp));
}

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