Submission #570527

#	Time	Username	Problem	Language	Result	Execution time	Memory
570527		Sam_a17	Chessboard (IZhO18_chessboard)	C++14	70 / 100	1773 ms	4580 KiB

chessboard

#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
//#include "temp.cpp"
#include <cstdio>
using namespace std;

#ifndef ONLINE_JUDGE
#define dbg(x) cerr << #x <<" "; print(x); cerr << endl;
#else
#define dbg(x)
#endif

#define sz(x) (int((x).size()))
#define len(x) (int)x.length()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define clr(x) (x).clear()
#define uniq(x) x.resize(unique(all(x)) - x.begin());
#define blt __builtin_popcount

#define pb push_back
#define popf pop_front
#define popb pop_back

void print(long long t) {cerr << t;}
void print(int t) {cerr << t;}
void print(string t) {cerr << t;}
void print(char t) {cerr << t;}
void print(double t) {cerr << t;}
void print(long double t) {cerr << t;}
void print(unsigned long long t) {cerr << t;}

template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(T v[],V n) {cerr << "["; for(int i = 0; i < n; i++) {print(v[i]); cerr << " "; } cerr << "]";}
template <class T, class V> void print(pair <T, V> p) {cerr << "{"; print(p.first); cerr << ","; print(p.second); cerr << "}";}
template <class T> void print(vector <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(set <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(multiset <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void print(map <T, V> v) {cerr << "[ "; for (auto i : v) {print(i); cerr << " ";} cerr << "]";}

#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
#define nl '\n'

// for grid problems
int dx[8] = {-1,0,1,0,1,-1,1,-1};
int dy[8] = {0,1,0,-1,1,1,-1,-1};

// lowest / (1 << 17) >= 1e5 / (1 << 18) >= 2e5 / (1 << 21) >= 1e6
void fastIO() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr); cout.tie(nullptr);
}
// file in/out
void setIO(string str = "") {
  fastIO();

  if (str != "") {
    freopen((str + ".in").c_str(), "r", stdin);
    freopen((str + ".out").c_str(), "w", stdout);
  }
}
// Indexed Set
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
vector<pair<pair< long long,  long long>, pair< long long,  long long>>> points;
long long ansi = 1e17;

vector<long long> get_divisors(long long n) {
  vector<long long> answ{1};
  for(long long i = 2; i * i <= n; i++) {
    if(n % i == 0) {
      answ.push_back(i);
      if(n / i != i) {
        answ.push_back(n / i);
      }
    }
  }
  return answ;
}

long long n, k;

void check(long long curr) {
  long long first = 0, second = 0;
  for(auto i: points) {
    long long x1 = i.first.first - 1, y1 = i.first.second - 1;
    long long x2 = i.second.first - 1, y2 = i.second.second - 1;

    // y1 -> y2

    long long block1 = y1 / curr, block2 = y2 / curr;

    if(block1 == block2) {
      long long toadd = y2 - y1 + 1;

      long long block11 = x1 / curr, block22 = x2 / curr;

      if(block11 == block22) {
        long long bazm = x2 - x1 + 1;
        if(block11 % 2 == block1 % 2) {
          first += bazm * toadd;
        } else {
          second += bazm * toadd;
        }
      }
      else {

        long long start = x1;
        while(start / curr == block11) {
          if(block11 % 2 == block1 % 2) {
            first += toadd;
          } else {
            second += toadd;
          }
          start++;
        }

        start = x2;

        while(start / curr == block22) {
          if(block22 % 2 == block1 % 2) {
            first += toadd;
          } else {
            second += toadd;
          }
          start--;
        }

        for(long long j = block11 + 1; j < block22; j++) {
          if(j % 2 == block1 % 2) {
            first += toadd * curr;
          } else {
            second += toadd * curr;
          }
        }
      }

    }
    else {
      long long block11 = x1 / curr, block22 = x2 / curr;

      if(block11 == block22) {
        long long toadd = x2 - x1 + 1;
        long long start = y1;

        while(start / curr == block1) {
          if(block11 % 2 == block1 % 2) {
            first += toadd;
          } else {
            second += toadd;
          }
          start++;
        }

        start = y2;
        while(start / curr == block2) {
          if(block11 % 2 == block2 % 2) {
            first += toadd;
          } else {
            second += toadd;
          }
          start--;
        }

        for(long long j = block1 + 1; j < block2; j++) {
          if(j % 2 == block11 % 2) {
            first += toadd * curr;
          } else {
            second += toadd * curr;
          }
        }
      }
      else {
        long long start = y1;
        long long needFirst = 0, needSecond = 0;
        while(start / curr == block1) {
          if(block11 % 2 == block1 % 2) {
            needFirst++;
          } else {
            needSecond++;
          }
          start++;
        }

        start = y2;
        while(start / curr == block2) {
          if(block11 % 2 == block2 % 2) {
            needFirst++;
          } else {
            needSecond++;
          }
          start--;
        }

        long long bazm = (curr - x1 % curr + 1);
        long long bazm2 = (x2 % curr + 1);
        first += needFirst * bazm;
        second += needSecond * bazm;
        first += needFirst * bazm2;
        second += needSecond * bazm2;

        for(long long j = block1 + 1; j < block2; j++) {
          if(j % 2 == block11 % 2) {
            first += curr * bazm;
            first += curr * bazm2;
            needFirst += curr;
          } else {
            second += curr * bazm;
            second += curr * bazm2;
            needSecond += curr;
          }
        }


        //
        for(long long j = block11 + 1; j < block22; j++) {
          if(block11 % 2 == j % 2) {
            first += needFirst * curr;
            second += needSecond * curr;
          } else {
            second += needFirst * curr;
            first += needSecond * curr;
          }
        }
      }
    }
  }

  long long row = (n * n) / (curr * curr);
  long long fs = row / 2, ss = row / 2;
  if(row & 1) {
    fs++;
  }

  fs = fs * (curr * curr);
  ss = ss * (curr * curr);

  ansi = min(ansi, fs - first + second);
  ansi = min(ansi, ss - second + first);
}

void solve_() {
  cin >> n >> k;
  vector<long long> div = get_divisors(n);

  for(int i = 1; i <= k; i++) {
    int x1, y1, x2, y2;
    cin >> x1 >> y1 >> x2 >> y2;
    points.push_back({{x1, y1}, {x2, y2}});
  }

  sort(all(points));

  for(auto i: div) {
    check(i);
  }

  printf("%lld\n", ansi);
}

int main() {
  setIO();

  auto solve = [&](int test_case)-> void {
    while(test_case--) {
      solve_();
    }
  };

  int test_cases = 1;
  solve(test_cases);

  return 0;
}

Compilation message (stderr)

chessboard.cpp: In function 'void setIO(std::string)':
chessboard.cpp:63:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   63 |     freopen((str + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
chessboard.cpp:64:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |     freopen((str + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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