Problem p03014 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <bits/stdc++.h>
using namespace std;

#define INF_LL (int64)1e18
// #define INF (int32)1e9
#define REP(i, n) for (int64 i = 0; i < (n); i++)
#define FOR(i, a, b) for (int64 i = (a); i < (b); i++)
#define all(x) x.begin(), x.end()
#define fs first
#define sc second

using int32 = int_fast32_t;
using uint32 = uint_fast32_t;
using int64 = int_fast64_t;
using uint64 = uint_fast64_t;
using PII = pair<int32, int32>;
using PLL = pair<int64, int64>;

const double eps = 1e-10;

template <typename A, typename B> inline void chmin(A &a, B b) {
  if (a > b)
    a = b;
}
template <typename A, typename B> inline void chmax(A &a, B b) {
  if (a < b)
    a = b;
}

template <typename T> vector<T> make_v(size_t a) { return vector<T>(a); }

template <typename T, typename... Ts> auto make_v(size_t a, Ts... ts) {
  return vector<decltype(make_v<T>(ts...))>(a, make_v<T>(ts...));
}

template <typename T, typename U, typename... V>
typename enable_if<is_same<T, U>::value != 0>::type fill_v(U &u, const V... v) {
  u = U(v...);
}

template <typename T, typename U, typename... V>
typename enable_if<is_same<T, U>::value == 0>::type fill_v(U &u, const V... v) {
  for (auto &e : u)
    fill_v<T>(e, v...);
}

class UnionFind {
private:
  ::std::vector<int_fast32_t> par, edge;
  size_t n;

public:
  UnionFind() {}
  UnionFind(size_t n) : n(n) {
    par.resize(n, -1);
    edge.resize(n, 0);
  }

  uint_fast32_t find(uint_fast32_t x) {
    return par[x] < 0 ? x : par[x] = find(par[x]);
  }

  size_t size(uint_fast32_t x) { return -par[find(x)]; }

  bool unite(uint_fast32_t x, uint_fast32_t y) {
    x = find(x);
    y = find(y);
    edge[x] += 1;
    if (x == y)
      return false;
    if (size(x) < size(y))
      std::swap(x, y);
    par[x] += par[y];
    edge[x] += edge[y];
    par[y] = x;
    return true;
  }

  bool same(uint_fast32_t x, uint_fast32_t y) { return find(x) == find(y); }

  size_t esize(uint_fast32_t x) { return edge[find(x)]; }
};

template <::std::uint_fast64_t mod> class ModInt {
private:
  using value_type = ::std::uint_fast64_t;
  value_type n;

public:
  ModInt() : n(0) {}
  ModInt(value_type n_) : n(n_ % mod) {}
  ModInt(const ModInt &m) : n(m.n) {}

  template <typename T> explicit operator T() const {
    return static_cast<T>(n);
  }
  value_type get() const { return n; }

  friend ::std::ostream &operator<<(::std::ostream &os, const ModInt<mod> &a) {
    return os << a.n;
  }

  friend ::std::istream &operator>>(::std::istream &is, ModInt<mod> &a) {
    value_type x;
    is >> x;
    a = ModInt<mod>(x);
    return is;
  }

  bool operator==(const ModInt &m) const { return n == m.n; }
  bool operator!=(const ModInt &m) const { return n != m.n; }
  ModInt &operator*=(const ModInt &m) {
    n = n * m.n % mod;
    return *this;
  }

  ModInt pow(value_type b) const {
    ModInt ans = 1, m = ModInt(*this);
    while (b) {
      if (b & 1)
        ans *= m;
      m *= m;
      b >>= 1;
    }
    return ans;
  }

  ModInt inv() const { return (*this).pow(mod - 2); }
  ModInt &operator+=(const ModInt &m) {
    n += m.n;
    n = (n < mod ? n : n - mod);
    return *this;
  }
  ModInt &operator-=(const ModInt &m) {
    n += mod - m.n;
    n = (n < mod ? n : n - mod);
    return *this;
  }
  ModInt &operator/=(const ModInt &m) {
    *this *= m.inv();
    return *this;
  }
  ModInt operator+(const ModInt &m) const { return ModInt(*this) += m; }
  ModInt operator-(const ModInt &m) const { return ModInt(*this) -= m; }
  ModInt operator*(const ModInt &m) const { return ModInt(*this) *= m; }
  ModInt operator/(const ModInt &m) const { return ModInt(*this) /= m; }
  ModInt &operator++() {
    n += 1;
    return *this;
  }
  ModInt &operator--() {
    n -= 1;
    return *this;
  }
  ModInt operator++(int) {
    ModInt old(n);
    n += 1;
    return old;
  }
  ModInt operator--(int) {
    ModInt old(n);
    n -= 1;
    return old;
  }
  ModInt operator-() const { return ModInt(mod - n); }
};

constexpr int64 mod = 1e9 + 7;
using Mint = ModInt<mod>;

int64 dx[4] = {-1, 0, 0, 1};
int64 dy[4] = {0, -1, 1, 0};
auto d = make_v<int64>(1, 1, 1);
vector<string> s;
int64 H, W;

bool in(int64 y, int64 x) {
  return 0 <= y && y < H && 0 <= x && x < W && s[y][x] != '#';
}

int64 calc(int64 y, int64 x) {
  int64 sum = 0;
  REP(dd, 4) {
    int64 cnt = 0;
    int64 ny = y, nx = x;
    while (in(ny, nx)) {
      if (d[dd][ny][nx] != -1) {
        cnt += d[dd][ny][nx];
        break;
      }
      ny += dy[dd];
      nx += dx[dd];
      cnt++;
    }
    ny = y;
    nx = x;
    while (in(ny, nx)) {
      if (d[dd][ny][nx] != -1)
        break;
      d[dd][ny][nx] = cnt - abs(ny - y) - abs(nx - x);
    }
    sum += d[dd][y][x];
  }
  return sum;
}

int main(void) {
  cin >> H >> W;
  d = make_v<int64>(4, H, W);
  fill_v<int64>(d, -1);

  s = vector<string>(H);
  REP(i, H) cin >> s[i];
  int64 res = 0;
  REP(i, H) {
    REP(j, W) { res = max(res, calc(i, j) - 3); }
  }
  cout << res << endl;
}


Fixed submission:
#include <bits/stdc++.h>
using namespace std;

#define INF_LL (int64)1e18
// #define INF (int32)1e9
#define REP(i, n) for (int64 i = 0; i < (n); i++)
#define FOR(i, a, b) for (int64 i = (a); i < (b); i++)
#define all(x) x.begin(), x.end()
#define fs first
#define sc second

using int32 = int_fast32_t;
using uint32 = uint_fast32_t;
using int64 = int_fast64_t;
using uint64 = uint_fast64_t;
using PII = pair<int32, int32>;
using PLL = pair<int64, int64>;

const double eps = 1e-10;

template <typename A, typename B> inline void chmin(A &a, B b) {
  if (a > b)
    a = b;
}
template <typename A, typename B> inline void chmax(A &a, B b) {
  if (a < b)
    a = b;
}

template <typename T> vector<T> make_v(size_t a) { return vector<T>(a); }

template <typename T, typename... Ts> auto make_v(size_t a, Ts... ts) {
  return vector<decltype(make_v<T>(ts...))>(a, make_v<T>(ts...));
}

template <typename T, typename U, typename... V>
typename enable_if<is_same<T, U>::value != 0>::type fill_v(U &u, const V... v) {
  u = U(v...);
}

template <typename T, typename U, typename... V>
typename enable_if<is_same<T, U>::value == 0>::type fill_v(U &u, const V... v) {
  for (auto &e : u)
    fill_v<T>(e, v...);
}

class UnionFind {
private:
  ::std::vector<int_fast32_t> par, edge;
  size_t n;

public:
  UnionFind() {}
  UnionFind(size_t n) : n(n) {
    par.resize(n, -1);
    edge.resize(n, 0);
  }

  uint_fast32_t find(uint_fast32_t x) {
    return par[x] < 0 ? x : par[x] = find(par[x]);
  }

  size_t size(uint_fast32_t x) { return -par[find(x)]; }

  bool unite(uint_fast32_t x, uint_fast32_t y) {
    x = find(x);
    y = find(y);
    edge[x] += 1;
    if (x == y)
      return false;
    if (size(x) < size(y))
      std::swap(x, y);
    par[x] += par[y];
    edge[x] += edge[y];
    par[y] = x;
    return true;
  }

  bool same(uint_fast32_t x, uint_fast32_t y) { return find(x) == find(y); }

  size_t esize(uint_fast32_t x) { return edge[find(x)]; }
};

template <::std::uint_fast64_t mod> class ModInt {
private:
  using value_type = ::std::uint_fast64_t;
  value_type n;

public:
  ModInt() : n(0) {}
  ModInt(value_type n_) : n(n_ % mod) {}
  ModInt(const ModInt &m) : n(m.n) {}

  template <typename T> explicit operator T() const {
    return static_cast<T>(n);
  }
  value_type get() const { return n; }

  friend ::std::ostream &operator<<(::std::ostream &os, const ModInt<mod> &a) {
    return os << a.n;
  }

  friend ::std::istream &operator>>(::std::istream &is, ModInt<mod> &a) {
    value_type x;
    is >> x;
    a = ModInt<mod>(x);
    return is;
  }

  bool operator==(const ModInt &m) const { return n == m.n; }
  bool operator!=(const ModInt &m) const { return n != m.n; }
  ModInt &operator*=(const ModInt &m) {
    n = n * m.n % mod;
    return *this;
  }

  ModInt pow(value_type b) const {
    ModInt ans = 1, m = ModInt(*this);
    while (b) {
      if (b & 1)
        ans *= m;
      m *= m;
      b >>= 1;
    }
    return ans;
  }

  ModInt inv() const { return (*this).pow(mod - 2); }
  ModInt &operator+=(const ModInt &m) {
    n += m.n;
    n = (n < mod ? n : n - mod);
    return *this;
  }
  ModInt &operator-=(const ModInt &m) {
    n += mod - m.n;
    n = (n < mod ? n : n - mod);
    return *this;
  }
  ModInt &operator/=(const ModInt &m) {
    *this *= m.inv();
    return *this;
  }
  ModInt operator+(const ModInt &m) const { return ModInt(*this) += m; }
  ModInt operator-(const ModInt &m) const { return ModInt(*this) -= m; }
  ModInt operator*(const ModInt &m) const { return ModInt(*this) *= m; }
  ModInt operator/(const ModInt &m) const { return ModInt(*this) /= m; }
  ModInt &operator++() {
    n += 1;
    return *this;
  }
  ModInt &operator--() {
    n -= 1;
    return *this;
  }
  ModInt operator++(int) {
    ModInt old(n);
    n += 1;
    return old;
  }
  ModInt operator--(int) {
    ModInt old(n);
    n -= 1;
    return old;
  }
  ModInt operator-() const { return ModInt(mod - n); }
};

constexpr int64 mod = 1e9 + 7;
using Mint = ModInt<mod>;

int64 dx[4] = {-1, 0, 0, 1};
int64 dy[4] = {0, -1, 1, 0};
auto d = make_v<int64>(1, 1, 1);
vector<string> s;
int64 H, W;

bool in(int64 y, int64 x) {
  return 0 <= y && y < H && 0 <= x && x < W && s[y][x] != '#';
}

int64 calc(int64 y, int64 x) {
  int64 sum = 0;
  REP(dd, 4) {
    int64 cnt = 0;
    int64 ny = y, nx = x;
    while (in(ny, nx)) {
      if (d[dd][ny][nx] != -1) {
        cnt += d[dd][ny][nx];
        break;
      }
      ny += dy[dd];
      nx += dx[dd];
      cnt++;
    }
    ny = y;
    nx = x;
    while (in(ny, nx)) {
      if (d[dd][ny][nx] != -1)
        break;
      d[dd][ny][nx] = cnt - abs(ny - y) - abs(nx - x);
      ny += dy[dd];
      nx += dx[dd];
    }
    sum += d[dd][y][x];
  }
  return sum;
}

int main(void) {
  cin >> H >> W;
  d = make_v<int64>(4, H, W);
  fill_v<int64>(d, -1);

  s = vector<string>(H);
  REP(i, H) cin >> s[i];
  int64 res = 0;
  REP(i, H) {
    REP(j, W) { res = max(res, calc(i, j) - 3); }
  }
  cout << res << endl;
}