Submission #833207

#	Time	Username	Problem	Language	Result	Execution time	Memory
833207		vjudge1	Bomb (IZhO17_bomb)	C++17	3 / 100	1099 ms	74032 KiB

bomb

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
// using ld = long double;
#define all(x) begin(x), end(x)
#ifdef LOCAL
#define debug(...) __VA_ARGS__;
#else
#define debug(...)
#endif

template<class A, class B> ostream& operator<<(ostream& os, const pair<A, B> &p);
template<class T> ostream& operator<<(ostream& os, const vector<T> &v);
template<class T, size_t N> ostream& operator<<(ostream& os, const array<T, N> &v);

template<class A, class B>
ostream& operator<<(ostream& os, const pair<A, B> &p) {
  return os << '(' << p.first << ',' << p.second << ')';
}
 
template<class T>
ostream& operator<<(ostream& os, const vector<T> &v) {
  os << '{'; bool fs = 1;
  for(auto &i : v) { if(!fs) os << ','; os << i; fs = 0; }
  return os << '}';
}

template<class T, size_t N>
ostream& operator<<(ostream& os, const array<T, N> &v) {
  os << '{'; bool fs = 1;
  for(auto &i : v) { if(!fs) os << ','; os << i; fs = 0; }
  return os << '}';
}

void init() {
}
 
void solve(int tt = 0) {
  int n, m; cin >> n >> m;
  vector a(n, vector<int>(m));
  bool ok = 0;
  for(auto &v : a) for(int &i : v) {
    char c; cin >> c;
    i = c - '0';
    ok |= i;
  }
  if(!ok) return void(cout << 0 << '\n');
  int h = 1e9, w = 1e9;
  {
    vector b = a;
    for(int i = 1; i < n; i++) {
      for(int j = 0; j < m; j++) {
        if(b[i][j] != 0) {
          b[i][j] += b[i-1][j];
        }
      }
    }
    debug({
      for(int i = 0; i < n; i++) {
        for(int j = 0; j < m; j++)
          cerr << b[i][j];
        cerr << '\n';
      }
    });
    for(int i = 0; i < n; i++) {
      for(int j = 0; j < m; j++) if(b[i][j] != 0 && (i == n-1 || (i < n-1 && b[i+1][j] == 0))) {
        h = min(h, b[i][j]);
      }
    }
  }

  vector pref(n, vector<int>(m));
  for(int i = 0; i < n; i++) {
    for(int j = 0; j < m; j++) {
      pref[i][j] = a[i][j];
      if(i) pref[i][j] += pref[i-1][j];
      if(j) pref[i][j] += pref[i][j-1];
      if(i > 0 && j > 0) pref[i][j] -= pref[i-1][j-1];
    }
  }
  const auto get = [&](int i1, int j1, int i2, int j2) -> int {
    int ans = pref[i2][j2];
    if(i1) ans -= pref[i1-1][j2];
    if(j1) ans -= pref[i2][j1-1];
    if(i1 && j1) ans += pref[i1-1][j1-1];
    return ans;
  };

  int ans = 0;
  vector b(n, vector<int>(m));
  for(int hh = 1; hh <= h; hh++) {
    for(int i = 0; i+hh-1 < n; i++) {
      for(int j = 0; j < m; j++) {
        b[i][j] = (get(i, j, i+hh-1, j) == hh);
      }
    }
    for(int j = 1; j < m; j++) {
      for(int i = 0; i+hh-1 < n; i++) {
        b[i][j] += b[i][j-1];
      }
    }
    for(int i = 0; i+hh-1 < n; i++) {
      for(int j = 0; j < m; j++) if(b[i][j] != 0 && (j == m-1 || (j < m-1 && b[i][j+1] == 0))) {
        ans = max(ans, h * w);
        w = min(w, b[i][j]);
      }
    }
  }
  cout << ans << '\n';
}

void reset() {
}
 
int main() {
  ios::sync_with_stdio(0); cin.tie(0);
  int t = 1; // cin >> t;
  init();
  for(int i = 1; i <= t; i++) solve(i), reset();
  return 0;
}

• Subtask 1: 3 / 100