Problem p03725 (C++)

Buggy submission (status: Runtime Error):
#include <algorithm>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <vector>
#define _USE_MATH_DEFINES
#include <cassert>
#include <cfloat>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
using namespace std;

#define EPS 1e-12
#define ull unsigned long long
#define ll long long
#define VI vector<ll>
#define PII pair<ll, ll>
#define VVI vector<vector<ll>>
#define REP(i, n) for (int i = 0, _n = (n); (i) < (int)_n; ++i)
#define RANGE(i, a, b) for (int i = (int)a, _b = (int)(b); (i) < _b; ++i)
#define FOR(i, c)                                                              \
  for (__typeof((c).begin()) i = (c).begin(); i != (c).end(); ++i)
#define ALL(c) (c).begin(), (c).end()
#define ALLR(c) (c).rbegin(), (c).rend()
#define PB push_back
#define MP(a, b) make_pair(a, b)
#define POPCOUNT __builtin_popcount
#define POPCOUNTLL __builtin_popcountll
#define CLEAR(table, v) memset(table, v, sizeof(table));
#define PRINT1(table, D0)                                                      \
  REP(d0, D0) cout << table[d0] << " ";                                        \
  cout << "\n";
#define PRINT2(table, D0, D1)                                                  \
  REP(d0, D0) {                                                                \
    REP(d1, D1) cout << table[d0][d1] << " ";                                  \
    cout << "\n";                                                              \
  }
#define PRINT3(table, D0, D1, D2)                                              \
  REP(d0, D0) {                                                                \
    REP(d1, D1) {                                                              \
      REP(d2, D2) cout << table[d0][d1][d2] << " ";                            \
      cout << "\n";                                                            \
    }                                                                          \
    cout << "\n";                                                              \
  }
#define UNIFORM_DOUBLE(a, b)                                                   \
  (((b - a) * (double)rand() / RAND_MAX) + a)      // [a, b)
#define UNIFORM_LL(a, b) (ll) UNIFORM_DOUBLE(a, b) // [a, b)
#define IN(v, lo, hi) ((lo) <= (v) && (v) < (hi))
#define DD(v) cout << #v << ": " << v << endl
template <typename T0, typename T1>
std::ostream &operator<<(std::ostream &os, const map<T0, T1> &v) {
  for (typename map<T0, T1>::const_iterator p = v.begin(); p != v.end(); p++) {
    os << p->first << ": " << p->second << " ";
  }
  return os;
}
template <typename T0, typename T1>
std::ostream &operator<<(std::ostream &os, const pair<T0, T1> &v) {
  os << v.first << ": " << v.second << " ";
  return os;
}
template <typename T>
std::ostream &operator<<(std::ostream &os, const vector<T> &v) {
  for (int i = 0; i < (int)v.size(); i++) {
    os << v[i] << " ";
  }
  return os;
}
template <typename T>
std::ostream &operator<<(std::ostream &os, const vector<vector<T>> &v) {
  for (int i = 0; i < (int)v.size(); i++) {
    os << v[i] << endl;
  }
  return os;
}
template <typename T>
std::ostream &operator<<(std::ostream &os, const set<T> &v) {
  vector<T> tmp(v.begin(), v.end());
  os << tmp;
  return os;
}
template <typename T>
std::ostream &operator<<(std::ostream &os, const deque<T> &v) {
  vector<T> tmp(v.begin(), v.end());
  os << tmp;
  return os;
}

#define MOD 1000000007LL
#define INF (1LL << 60)

int main() {
  // ios::sync_with_stdio(false);
  ll W, H, K;
  string s;
  while (cin >> H >> W >> K) {
    vector<string> w(H);
    deque<PII> q;
    VVI p(H, VI(W, INF));
    REP(i, H) {
      cin >> w[i];
      REP(j, W) if (w[i][j] == 'S') {
        q.push_back(MP(j, i));
        p[j][i] = 0;
      }
    }
    int dx[] = {0, 0, 1, -1};
    int dy[] = {1, -1, 0, 0};
    while (q.size()) {
      PII c = q.front();
      q.pop_front();
      ll x = c.first;
      ll y = c.second;
      REP(d, 4) {
        ll nx = x + dx[d];
        ll ny = y + dy[d];
        ll ncost = p[y][x] + 1;
        if (IN(nx, 0, W) && IN(ny, 0, H) && w[ny][nx] == '.' &&
            p[ny][nx] > ncost) {
          p[ny][nx] = ncost;
          q.push_back(MP(nx, ny));
        }
      }
    }
    //		DD(p);
    ll ans = INF;
    REP(y, H) REP(x, W) if (p[y][x] <= K) {
      ans = min(ans, 1 + (x + K - 1) / K);
      ans = min(ans, 1 + (W - 1 - x + K - 1) / K);
      ans = min(ans, 1 + (y + K - 1) / K);
      ans = min(ans, 1 + (H - 1 - y + K - 1) / K);
    }
    cout << ans << endl;
  }

  return 0;
}


Fixed submission:
#include <algorithm>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <vector>
#define _USE_MATH_DEFINES
#include <cassert>
#include <cfloat>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
using namespace std;

#define EPS 1e-12
#define ull unsigned long long
#define ll long long
#define VI vector<ll>
#define PII pair<ll, ll>
#define VVI vector<vector<ll>>
#define REP(i, n) for (int i = 0, _n = (n); (i) < (int)_n; ++i)
#define RANGE(i, a, b) for (int i = (int)a, _b = (int)(b); (i) < _b; ++i)
#define FOR(i, c)                                                              \
  for (__typeof((c).begin()) i = (c).begin(); i != (c).end(); ++i)
#define ALL(c) (c).begin(), (c).end()
#define ALLR(c) (c).rbegin(), (c).rend()
#define PB push_back
#define MP(a, b) make_pair(a, b)
#define POPCOUNT __builtin_popcount
#define POPCOUNTLL __builtin_popcountll
#define CLEAR(table, v) memset(table, v, sizeof(table));
#define PRINT1(table, D0)                                                      \
  REP(d0, D0) cout << table[d0] << " ";                                        \
  cout << "\n";
#define PRINT2(table, D0, D1)                                                  \
  REP(d0, D0) {                                                                \
    REP(d1, D1) cout << table[d0][d1] << " ";                                  \
    cout << "\n";                                                              \
  }
#define PRINT3(table, D0, D1, D2)                                              \
  REP(d0, D0) {                                                                \
    REP(d1, D1) {                                                              \
      REP(d2, D2) cout << table[d0][d1][d2] << " ";                            \
      cout << "\n";                                                            \
    }                                                                          \
    cout << "\n";                                                              \
  }
#define UNIFORM_DOUBLE(a, b)                                                   \
  (((b - a) * (double)rand() / RAND_MAX) + a)      // [a, b)
#define UNIFORM_LL(a, b) (ll) UNIFORM_DOUBLE(a, b) // [a, b)
#define IN(v, lo, hi) ((lo) <= (v) && (v) < (hi))
#define DD(v) cout << #v << ": " << v << endl
template <typename T0, typename T1>
std::ostream &operator<<(std::ostream &os, const map<T0, T1> &v) {
  for (typename map<T0, T1>::const_iterator p = v.begin(); p != v.end(); p++) {
    os << p->first << ": " << p->second << " ";
  }
  return os;
}
template <typename T0, typename T1>
std::ostream &operator<<(std::ostream &os, const pair<T0, T1> &v) {
  os << v.first << ": " << v.second << " ";
  return os;
}
template <typename T>
std::ostream &operator<<(std::ostream &os, const vector<T> &v) {
  for (int i = 0; i < (int)v.size(); i++) {
    os << v[i] << " ";
  }
  return os;
}
template <typename T>
std::ostream &operator<<(std::ostream &os, const vector<vector<T>> &v) {
  for (int i = 0; i < (int)v.size(); i++) {
    os << v[i] << endl;
  }
  return os;
}
template <typename T>
std::ostream &operator<<(std::ostream &os, const set<T> &v) {
  vector<T> tmp(v.begin(), v.end());
  os << tmp;
  return os;
}
template <typename T>
std::ostream &operator<<(std::ostream &os, const deque<T> &v) {
  vector<T> tmp(v.begin(), v.end());
  os << tmp;
  return os;
}

#define MOD 1000000007LL
#define INF (1LL << 60)

int main() {
  // ios::sync_with_stdio(false);
  ll W, H, K;
  string s;
  while (cin >> H >> W >> K) {
    vector<string> w(H);
    deque<PII> q;
    VVI p(H, VI(W, INF));
    REP(y, H) {
      cin >> w[y];
      REP(x, W) if (w[y][x] == 'S') {
        q.push_back(MP(x, y));
        p[y][x] = 0;
      }
    }
    int dx[] = {0, 0, 1, -1};
    int dy[] = {1, -1, 0, 0};
    while (q.size()) {
      PII c = q.front();
      q.pop_front();
      ll x = c.first;
      ll y = c.second;
      REP(d, 4) {
        ll nx = x + dx[d];
        ll ny = y + dy[d];
        ll ncost = p[y][x] + 1;
        if (IN(nx, 0, W) && IN(ny, 0, H) && w[ny][nx] == '.' &&
            p[ny][nx] > ncost) {
          p[ny][nx] = ncost;
          q.push_back(MP(nx, ny));
        }
      }
    }
    //		DD(p);
    ll ans = INF;
    REP(y, H) REP(x, W) if (p[y][x] <= K) {
      ans = min(ans, 1 + (x + K - 1) / K);
      ans = min(ans, 1 + (W - 1 - x + K - 1) / K);
      ans = min(ans, 1 + (y + K - 1) / K);
      ans = min(ans, 1 + (H - 1 - y + K - 1) / K);
    }
    cout << ans << endl;
  }

  return 0;
}