Submission #970656

#	Time	Username	Problem	Language	Result	Execution time	Memory
970656		nguyentunglam	Radio Towers (IOI22_towers)	C++17	100 / 100	1294 ms	317476 KiB

towers

#include "towers.h"
#include<bits/stdc++.h>
#define all(v) v.begin(), v.end()
using namespace std;

const int N = 1e5 + 10, S = 1e5 * 20 * 4;

int h[N], lg[N], mx[20][N], mn[20][N], L[N], R[N];

int n;

vector<int> rrh, pos[2 * N];

int idx(int x) {
  return upper_bound(all(rrh), x) - rrh.begin();
}

struct ITSUM {
struct node {
  int left, right, val;
  node () {
    left = right = val = 0;
  }
} T[S];

int cnt;
int it[2 * N];

void pass (int x, int y) {
  T[it[x] = ++cnt] = T[it[y]];
}

void up(int s, int l, int r, int pos, int val) {
  if (l == r) {
    T[s].val += val;
    return;
  }
  int mid = l + r >> 1;
  if (pos <= mid) {
    T[++cnt] = T[T[s].left];
    T[s].left = cnt;
    up(T[s].left, l, mid, pos, val);
  }
  else {
    T[++cnt] = T[T[s].right];
    T[s].right = cnt;
    up(T[s].right, mid + 1, r, pos, val);
  }
  T[s].val = T[T[s].left].val + T[T[s].right].val;
}

int get(int s, int l, int r, int from, int to) {
  if (l > to || r < from || s == 0) return 0;
  if (from <= l && r <= to) return T[s].val;
  int mid = l + r >> 1;
  return get(T[s].left, l, mid, from, to) + get(T[s].right, mid + 1, r, from, to);
}
} itsum;

struct ITMAX {
struct node {
  int left, right, val;
  node () {
    left = right = 0;
    val = -1e9;
  }
} T[S];

int cnt;
int it[2 * N];

void pass (int x, int y) {
  T[it[x] = ++cnt] = T[it[y]];
}

void up(int s, int l, int r, int from , int to, int val) {
  if (l > to || r < from) return;
  if (from <= l && r <= to) {
    T[s].val = max(T[s].val, val);
    return;
  }
  int mid = l + r >> 1;
  T[++cnt] = T[T[s].left];
  T[s].left = cnt;
  T[++cnt] = T[T[s].right];
  T[s].right = cnt;
  up(T[s].left, l, mid, from, to, val);
  up(T[s].right, mid + 1, r, from, to, val);
}

int get(int s, int l, int r, int pos) {
//  cerr << s << " " << l << " " << r << endl;
  if (l == r || !s) return T[s].val;
  int mid = l + r >> 1;
//  cout << T[s].left << e
//  exit(0);
  if (pos <= mid) return max(T[s].val, get(T[s].left, l, mid, pos));
  return max(T[s].val, get(T[s].right, mid + 1, r, pos));
}
} itmax0, itmax1;

int getmax(int l, int r) {
  if (l > r) return -1e9;
  int k = lg[r - l + 1];
  return max(mx[k][l], mx[k][r - (1 << k) + 1]);
}

int best (int x, int y) {
  return h[x] < h[y] ? x : y;
}

int getmin(int l, int r) {
  if (l > r) return -1e9;
  int k = lg[r - l + 1];
  return best(mn[k][l], mn[k][r - (1 << k) + 1]);
}

priority_queue<int> Q[N];

bool alive[N];

void init(int N, std::vector<int> H) {
  n = N;
  for(int i = 0; i < n; i++) h[i] = H[i];
  stack<int> st;
  for(int i = 0; i < n; i++) {
    while (!st.empty() && h[st.top()] >= h[i]) st.pop();
    L[i] = st.empty() ? -1 : st.top();
    st.push(i);
  }
  while (!st.empty()) st.pop();
  for(int i = n - 1; i >= 0; i--) {
    while (!st.empty() && h[st.top()] >= h[i]) st.pop();
    R[i] = st.empty() ? n : st.top();
    st.push(i);
  }

  for(int i = 0; i < n; i++) mx[0][i] = h[i], mn[0][i] = i;
  for(int i = 2; i <= n; i++) lg[i] = lg[i / 2] + 1;
  for(int j = 1; j <= lg[n]; j++) for(int i = 0; i + (1 << j) - 1 < n; i++) {
    mx[j][i] = max(mx[j - 1][i], mx[j - 1][i + (1 << j - 1)]);
    mn[j][i] = best(mn[j - 1][i], mn[j - 1][i + (1 << j - 1)]);
  }

  for(int i = 0; i < n; i++) {
    int tmp = min(getmax(L[i] + 1, i - 1), getmax(i + 1, R[i] - 1)) - h[i];
    rrh.push_back(getmax(L[i] + 1, i - 1) - h[i]);
    rrh.push_back(getmax(i + 1, R[i] - 1) - h[i]);
  }

  sort(all(rrh));
  rrh.resize(unique(all(rrh)) - rrh.begin());

  int m = rrh.size();

  for(int i = 0; i < n; i++) {
    int tmp = min(getmax(L[i] + 1, i - 1), getmax(i + 1, R[i] - 1)) - h[i];
//    cout << getmax(L[i] + 1, i - 1) << " " << getmax(i + 1, R[i] - 1) << " " << i << endl;
    pos[idx(tmp)].push_back(i);
  }

  for(int val = m; val >= 1; val--) {
    itsum.pass(val, val + 1);
    for(int &i : pos[val]) {
      itsum.up(itsum.it[val], 0, n - 1, i, 1);
    } pos[val].clear();
  }

  for(int i = 0; i < n; i++) {
    int tmp = getmax(i + 1, R[i] - 1) - h[i];
//    cout << idx(tmp) << endl;
    pos[idx(tmp)].push_back(i);
  }

  for(int val = m; val >= 1; val--) {
    itmax0.pass(val, val + 1);
    for(int &i : pos[val]) {
      itmax0.up(itmax0.it[val], 0, n - 1, L[i] + 1, i, -i);
//      cout << itmax0.get(itmax0.it[val], 0, n - 1, i) << endl;
    } pos[val].clear();
  }

  for(int i = 0; i < n; i++) {
    int tmp = getmax(L[i] + 1, i - 1) - h[i];
    pos[idx(tmp)].push_back(i);
  }

  for(int val = m; val >= 1; val--) {
    itmax1.pass(val, val + 1);
    for(int &i : pos[val]) {
      itmax1.up(itmax1.it[val], 0, n - 1, i, R[i] - 1, i);
    }
  }
}

int max_towers(int l, int r, int d) {
  int tmp = idx(d - 1) + 1;

  int ans = itsum.get(itsum.it[tmp], 0, n - 1, l, r);

//  cout << ans << endl;
  int left = -itmax0.get(itmax0.it[tmp], 0, n - 1, l);
  int right = itmax1.get(itmax1.it[tmp], 0, n - 1, r);


  int smallest = getmin(l, r);
//  cout << smallest << " " << left << " " << right << endl;

  if (left >= l && left <= r && left != smallest && getmax(L[left] + 1, left - 1) - d < h[left]) {
    ans++;
  }
//  exit(0);

  if (right >= l && right <= r && right != smallest && getmax(right + 1, R[right] - 1) - d < h[right]) {
    ans++;
  }

  if (getmax(L[smallest] + 1, smallest - 1) - d < h[smallest] || getmax(smallest + 1, R[smallest] - 1) - d < h[smallest]) ans++;

  return ans;
}

#ifdef ngu
int main() {
  freopen ("task.inp", "r", stdin);
  freopen ("task.out", "w", stdout);
  int N, Q;
  assert(2 == scanf("%d %d", &N, &Q));
  std::vector<int> H(N);
  for (int i = 0; i < N; ++i) {
    assert(1 == scanf("%d", &H[i]));
  }
  init(N, H);

  for (int i = 0; i < Q; ++i) {
    int L, R, D;
    assert(3 == scanf("%d %d %d", &L, &R, &D));
    printf("%d\n", max_towers(L, R, D));
  }
  return 0;
}
#endif // ngu

Compilation message (stderr)

towers.cpp: In member function 'void ITSUM::up(int, int, int, int, int)':
towers.cpp:38:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   38 |   int mid = l + r >> 1;
      |             ~~^~~
towers.cpp: In member function 'int ITSUM::get(int, int, int, int, int)':
towers.cpp:55:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   55 |   int mid = l + r >> 1;
      |             ~~^~~
towers.cpp: In member function 'void ITMAX::up(int, int, int, int, int, int)':
towers.cpp:82:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   82 |   int mid = l + r >> 1;
      |             ~~^~~
towers.cpp: In member function 'int ITMAX::get(int, int, int, int)':
towers.cpp:94:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   94 |   int mid = l + r >> 1;
      |             ~~^~~
towers.cpp: In function 'void init(int, std::vector<int>)':
towers.cpp:141:56: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
  141 |     mx[j][i] = max(mx[j - 1][i], mx[j - 1][i + (1 << j - 1)]);
      |                                                      ~~^~~
towers.cpp:142:57: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
  142 |     mn[j][i] = best(mn[j - 1][i], mn[j - 1][i + (1 << j - 1)]);
      |                                                       ~~^~~
towers.cpp:146:9: warning: unused variable 'tmp' [-Wunused-variable]
  146 |     int tmp = min(getmax(L[i] + 1, i - 1), getmax(i + 1, R[i] - 1)) - h[i];
      |         ^~~

• 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