Submission #879192

#	Time	Username	Problem	Language	Result	Execution time	Memory
879192		MilosMilutinovic	Plus Minus (BOI17_plusminus)	C++14	100 / 100	151 ms	14340 KiB

plusminus

#include <bits/stdc++.h>

using namespace std;

const int md = 1e9 + 7;

int ckmul(int a, int b) {
  return a * 1LL * b % md;
}

int ckadd(int a, int b) {
  return a + b >= md ? a + b - md : a + b;
}

int powmod(int x, int k) {
  int res = 1;
  while (k) {
    if (k & 1) {
      res = ckmul(res, x);
    }
    x = ckmul(x, x);
    k >>= 1;
  }
  return res;
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, m, k;
  cin >> n >> m >> k;
  vector<char> c(k);
  vector<int> x(k);
  vector<int> y(k);
  for (int i = 0; i < k; i++) {
    cin >> c[i] >> x[i] >> y[i];
  }
  int ans = 0;
  {
    // row
    map<int, vector<int>> mp;
    for (int i = 0; i < k; i++) {
      mp[x[i]].push_back(i);
    }
    bool ok = true;
    for (auto& p : mp) {
      vector<vector<bool>> f(2, vector<bool>(2));
      for (int i : p.second) {
        int p = (y[i] % 2);
        int v = (c[i] == '+' ? 0 : 1);
        f[p][v] = true;
      }
      if ((f[0][0] && f[0][1]) || (f[1][0] && f[1][1]) || (f[0][0] && f[1][0]) || (f[0][1] && f[1][1])) {
        ok = false;  
      }
    }
    if (ok) {
      ans = ckadd(ans, powmod(2, n - (int) mp.size()));
    }
  }
  {
    // col
    map<int, vector<int>> mp;
    for (int i = 0; i < k; i++) {
      mp[y[i]].push_back(i);
    }
    bool ok = true;
    for (auto& p : mp) {
      vector<vector<bool>> f(2, vector<bool>(2, false));
      for (int i : p.second) {
        int p = (x[i] % 2);
        int v = (c[i] == '+' ? 0 : 1);
        f[p][v] = true;
      }
      if ((f[0][0] && f[0][1]) || (f[1][0] && f[1][1]) || (f[0][0] && f[1][0]) || (f[0][1] && f[1][1])) {
        ok = false;  
      }
    }
    if (ok) {
      ans = ckadd(ans, powmod(2, m - (int) mp.size()));
    }
  }
  {
    for (char ch : {'+', '-'}) {
      bool ok = true;
      for (int i = 0; i < k; i++) {
        char v = ((x[i] + y[i]) % 2 == 0 ? ch : (ch ^ '-' ^ '+'));
        if (v != c[i]) {
          ok = false;
        }
      }
      if (ok) {
        ans -= 1;
        if (ans < 0) {
          ans += md;
        }
      }
    }
  }
  cout << ans << '\n';
  return 0;
}

• Subtask 1: 12 / 12
• Subtask 2: 42 / 42
• Subtask 3: 46 / 46