Submission #503139

#	Time	Username	Problem	Language	Result	Execution time	Memory
503139		Pety	Chessboard (IZhO18_chessboard)	C++14	39 / 100	657 ms	8452 KiB

chessboard

#include <bits/stdc++.h>

#define ll long long
#define ld long double

using namespace std;

const ll MOD = 1e9 + 7;
const ll INF = 1e9;
const int N = 1e5 + 2;

int n, sum[100002], k, lazy[400002], aint[400002];

struct query {
  int type, l, r;
  bool operator < (const query &other) {
    return type < other.type;
  }
};
vector<query>q[100002];

void build (int nod, int st, int dr) {
  aint[nod] = sum[dr] - (st > 0 ? sum[st - 1] : 0);
  if (st == dr)
    return;
  int mij = (st + dr) / 2;
  build(2 * nod, st, mij);
  build(2 * nod + 1, mij + 1, dr);
}

void push (int nod, int st, int dr) {
  if (lazy[nod] != -1) {
    if (st != dr) {
      lazy[2 * nod] = lazy[nod];
      lazy[2 * nod + 1] = lazy[nod];
    }
    if (lazy[nod] == 0)
      aint[nod] = sum[dr] - (st > 0 ? sum[st - 1] : 0);
    else
      aint[nod] = (dr - st + 1) - (sum[dr] - (st > 0 ? sum[st - 1] : 0));
  }
  lazy[nod] = -1;
}

void update (int nod, int st, int dr, int a, int b, int val) {
  push(nod, st, dr);
  if (a <= st && dr <= b) {
    if (val == 0)
      aint[nod] = sum[dr] - (st > 0 ? sum[st - 1] : 0);
    else
      aint[nod] = (dr - st + 1) - (sum[dr] - (st > 0 ? sum[st - 1] : 0));
    if (st != dr) {
      lazy[2 * nod] = val;
      lazy[2 * nod + 1] = val;
    }
    return;
  }
  int  mij = (st + dr) / 2;
  if (a <= mij)
    update(2 * nod, st, mij, a, b, val);
  else
    update(2 * nod + 1, mij + 1, dr, a, b, val);
  aint[nod] = aint[2 * nod] + aint[2 * nod + 1];
}


int main()
{
  ios_base::sync_with_stdio(false);
  cin.tie(0); cout.tie(0);
  cin >> n >> k;
  while (k--) {
    int x1, y1, x2, y2;
    cin >> x1 >> y1 >> x2 >> y2;
    x1--; y1--; x2--; y2--;
    q[x1].push_back({1, y1, y2});
    q[x2 + 1].push_back({0, y1, y2});
  }
  for (int i = 0; i < n; i++)
    sort(q[i].begin(), q[i].end());
  ll sol = n * n;
  for (int l = 1; l < n; l++) {
    if (n % l == 0) {
      for (int i = 0; i < n; i++) {
        sum[i] = (i / l) % 2 + (i > 0 ? sum[i - 1] : 0);
      }
      ll nr = 0;
      for (int i = 1; i <= 4 * n; i++) {
        lazy[i] = -1;
      }
      build(1, 0, n - 1);
      for (int i = 0; i < n; i++) {
        for (auto it : q[i]) {
          if (it.type == 0) 
            update(1, 0, n - 1, it.l, it.r, 0);
          else
            update(1, 0, n - 1, it.l, it.r, 1);
        }
        if ((i / l) % 2)
          nr += n - aint[1];
        else
          nr += aint[1];
      }
      sol = min(sol, min(nr, 1l * n  *n - nr));
    }
  }
  cout << sol;
  return 0;
}

• Subtask 1: 8 / 8
• Subtask 2: 0 / 8
• Subtask 3: 15 / 15
• Subtask 4: 16 / 16
• Subtask 5: 0 / 23
• Subtask 6: 0 / 30