Problem p02644 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <bits/stdc++.h>
///...................................*****.................................................///
///        Author :  Raihan Khan Raka  ( raihankhanraka@gmail.com ) ///
///                  Department of Computer Science /// & Engineering ///
///                  Comilla University , Bangladesh. ///
///...................................*****.................................................///

/*....................................Values................................................*/
#define p5 100007
#define p6 1000007
#define PI acos(-1)
#define M 1000000007
#define inf 1LL << 62
#define white 0
#define gray 1
#define black 2
/*....................................Functions.............................................*/
#define sqr(x) x *x
#define sc scanf
#define pf printf
#define pfn printf("\n")
#define scin(x) sc("%d", &(x))
#define scin2(xx, zz) scanf("%d %d", &xx, &zz)
#define scln(x) sc("%lld", &(x))
#define scln2(xx, zz) scanf("%lld %lld", &xx, &zz)
#define min3(a, b, c) min(a, b < c ? b : c)
#define max3(a, b, c) max(a, b > c ? b : c)
#define all(v) v.begin(), v.end()
#define ok cout << "ok" << endl
#define mem(x, y) memset(x, y, sizeof(x))
#define clr(a) a.clear()
#define READ(f) freopen(f, "r", stdin)
#define WRITE(f) freopen(f, "w", stdout)

/*...................................Data_Types............................................*/
#define lli long long int
#define ull unsigned long long int
#define pii pair<int, int>
#define pll pair<ll, ll>
#define veci vector<int>
#define vecl vector<long long int>
#define vecp vector<pair<int, int>>
#define mapstrint map<string, int>
#define mapstrstr map<string, string>
#define mapint map<int, int>
#define uset unordered_set
#define umap unordered_map
#define pq priority_queue

#define pb push_back
#define mp make_pair
#define ff first
#define ss second

/*.....................................Loops...............................................*/
#define rep(i, a, b) for (i = a; i < b; i++)
#define rev(i, a, b) for (i = a; i >= b; i--)
#define repx(i, a, b, x) for (i = a; i < b; i += x)
#define test(t)                                                                \
  int t;                                                                       \
  scin(t);                                                                     \
  while (t--)
#define doshomik(x) fixed << setprecision(x)
#define IOS                                                                    \
  ios::sync_with_stdio(0);                                                     \
  cin.tie(0);                                                                  \
  cout.tie(0);
#define error(args...)                                                         \
  {                                                                            \
    string _s = #args;                                                         \
    replace(_s.begin(), _s.end(), ',', ' ');                                   \
    stringstream _ss(_s);                                                      \
    istream_iterator<string> _it(_ss);                                         \
    err(_it, args);                                                            \
  }
// int month[]={31,28,31,30,31,30,31,31,30,31,30,31};

///------------------------------- Mudular
///functions----------------------------------------
/*
inline lli power(lli x, lli y){ lli temp; if( y == 0) return 1; temp = power(x,
y/2); if (y%2 == 0) return temp*temp; else return x*temp*temp; } inline lli
add(lli a, lli b) {a += b; return a >= M ? a - M : a;} inline lli sub(lli a, lli
b) {a -= b; return a < 0 ? a + M : a;} inline lli mul(lli a, lli b) {return  (a
* b) % M;} lli gcd(lli x,lli y)
{
    if(x==0) return y;
    return gcd(y%x,x);
}
lli bigmod(lli n, lli k )
{
    lli ans=1;
    while(k)
    {
        if(k&1)
            ans=(ans*n)%M;
        k=k>>1;
        n=(n*n)%M;
    }

    return ans;
}
*/
///----------------------------------Graph
///moves----------------------------------------

int dx4[5] = {1, -1, 0, 0};
int dy4[5] = {0, 0, 1, -1};
int dx8[9] = {0, 0, 1, -1, -1, 1, -1, 1};
int dy8[9] = {-1, 1, 0, 0, 1, 1, -1, -1};
int knightx[9] = {-2, -2, -1, -1, 1, 1, 2, 2};
int knighty[9] = {-1, 1, -2, 2, -2, 2, -1, 1};
bool valid(int r, int c, int x, int y) {
  if (x >= 1 && x <= r && y >= 1 && y <= c)
    return 1;
  return 0;
}

using namespace std;

void err(istream_iterator<string> it) { cerr << endl; }
template <typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
  cerr << "[ " << *it << " = " << a << " ] ";
  err(++it, args...);
}
///...............................Code Starts
///Here........................................

vector<vector<lli>> dp;
vector<vector<char>> v;
lli h, w, k;
void initialize_dp(vector<vector<lli>> &dp) {
  lli i, j;
  rep(i, 1, h + 1) rep(j, 1, w + 1) dp[i][j] = 1LL << 32;
}
lli bfs(lli x1, lli y1, lli x2, lli y2) {
  lli i, j, x, y, a, b, level = 0;

  queue<pair<lli, lli>> q;
  q.push({x1, y1});
  dp[x1][y1] = level;

  while (!q.empty()) {
    x = q.front().ff;
    y = q.front().ss;
    // vis[x][y]=1;
    q.pop();

    rep(i, 0, 4) {
      rep(j, 1, k + 1) {
        a = x + (j * dx4[i]);
        b = y + (j * dy4[i]);

        if (valid(h, w, a, b)) {
          if (v[a][b] != '@' and dp[a][b] > dp[x][y]) {
            q.push({a, b}), dp[a][b] = min(dp[a][b], 1 + dp[x][y]);
          } else
            break;
        } else
          break;
      }
    }
  }
  if (dp[x2][y2] == (1LL << 32))
    dp[x2][y2] = -1;
  return dp[x2][y2];
}

int main() {
  IOS;
  lli x1, x2, y1, y2, i, j;

  cin >> h >> w >> k >> x1 >> y1 >> x2 >> y2;
  v.resize(h + 3);
  dp.resize(h + 3);

  rep(i, 1, h + 1) {
    v[i].resize(w + 3);
    dp[i].resize(w + 3);
    rep(j, 1, w + 1) { cin >> v[i][j]; }
  }

  initialize_dp(dp);
  dp[x1][y1] = 0;
  lli mini = bfs(x1, y1, x2, y2);

  cout << mini << endl;

  return 0;
}


Fixed submission:
#include <bits/stdc++.h>
///...................................*****.................................................///
///        Author :  Raihan Khan Raka  ( raihankhanraka@gmail.com ) ///
///                  Department of Computer Science /// & Engineering ///
///                  Comilla University , Bangladesh. ///
///...................................*****.................................................///

/*....................................Values................................................*/
#define p5 100007
#define p6 1000007
#define PI acos(-1)
#define M 1000000007
#define inf 1LL << 62
#define white 0
#define gray 1
#define black 2
/*....................................Functions.............................................*/
#define sqr(x) x *x
#define sc scanf
#define pf printf
#define pfn printf("\n")
#define scin(x) sc("%d", &(x))
#define scin2(xx, zz) scanf("%d %d", &xx, &zz)
#define scln(x) sc("%lld", &(x))
#define scln2(xx, zz) scanf("%lld %lld", &xx, &zz)
#define min3(a, b, c) min(a, b < c ? b : c)
#define max3(a, b, c) max(a, b > c ? b : c)
#define all(v) v.begin(), v.end()
#define ok cout << "ok" << endl
#define mem(x, y) memset(x, y, sizeof(x))
#define clr(a) a.clear()
#define READ(f) freopen(f, "r", stdin)
#define WRITE(f) freopen(f, "w", stdout)

/*...................................Data_Types............................................*/
#define lli long long int
#define ull unsigned long long int
#define pii pair<int, int>
#define pll pair<ll, ll>
#define veci vector<int>
#define vecl vector<long long int>
#define vecp vector<pair<int, int>>
#define mapstrint map<string, int>
#define mapstrstr map<string, string>
#define mapint map<int, int>
#define uset unordered_set
#define umap unordered_map
#define pq priority_queue

#define pb push_back
#define mp make_pair
#define ff first
#define ss second

/*.....................................Loops...............................................*/
#define rep(i, a, b) for (i = a; i < b; i++)
#define rev(i, a, b) for (i = a; i >= b; i--)
#define repx(i, a, b, x) for (i = a; i < b; i += x)
#define test(t)                                                                \
  int t;                                                                       \
  scin(t);                                                                     \
  while (t--)
#define doshomik(x) fixed << setprecision(x)
#define IOS                                                                    \
  ios::sync_with_stdio(0);                                                     \
  cin.tie(0);                                                                  \
  cout.tie(0);
#define error(args...)                                                         \
  {                                                                            \
    string _s = #args;                                                         \
    replace(_s.begin(), _s.end(), ',', ' ');                                   \
    stringstream _ss(_s);                                                      \
    istream_iterator<string> _it(_ss);                                         \
    err(_it, args);                                                            \
  }
// int month[]={31,28,31,30,31,30,31,31,30,31,30,31};

///------------------------------- Mudular
///functions----------------------------------------
/*
inline lli power(lli x, lli y){ lli temp; if( y == 0) return 1; temp = power(x,
y/2); if (y%2 == 0) return temp*temp; else return x*temp*temp; } inline lli
add(lli a, lli b) {a += b; return a >= M ? a - M : a;} inline lli sub(lli a, lli
b) {a -= b; return a < 0 ? a + M : a;} inline lli mul(lli a, lli b) {return  (a
* b) % M;} lli gcd(lli x,lli y)
{
    if(x==0) return y;
    return gcd(y%x,x);
}
lli bigmod(lli n, lli k )
{
    lli ans=1;
    while(k)
    {
        if(k&1)
            ans=(ans*n)%M;
        k=k>>1;
        n=(n*n)%M;
    }

    return ans;
}
*/
///----------------------------------Graph
///moves----------------------------------------

int dx4[5] = {1, -1, 0, 0};
int dy4[5] = {0, 0, 1, -1};
int dx8[9] = {0, 0, 1, -1, -1, 1, -1, 1};
int dy8[9] = {-1, 1, 0, 0, 1, 1, -1, -1};
int knightx[9] = {-2, -2, -1, -1, 1, 1, 2, 2};
int knighty[9] = {-1, 1, -2, 2, -2, 2, -1, 1};
bool valid(int r, int c, int x, int y) {
  if (x >= 1 && x <= r && y >= 1 && y <= c)
    return 1;
  return 0;
}

using namespace std;

void err(istream_iterator<string> it) { cerr << endl; }
template <typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
  cerr << "[ " << *it << " = " << a << " ] ";
  err(++it, args...);
}
///...............................Code Starts
///Here........................................

vector<vector<lli>> dp;
vector<vector<char>> v;
lli h, w, k;
void initialize_dp(vector<vector<lli>> &dp) {
  lli i, j;
  rep(i, 1, h + 1) rep(j, 1, w + 1) dp[i][j] = 1LL << 32;
}
lli bfs(lli x1, lli y1, lli x2, lli y2) {
  lli i, j, x, y, a, b, level = 0;

  queue<pair<lli, lli>> q;
  q.push({x1, y1});
  dp[x1][y1] = level;

  while (!q.empty()) {
    x = q.front().ff;
    y = q.front().ss;
    // vis[x][y]=1;
    q.pop();

    rep(i, 0, 4) {
      rep(j, 1, k + 1) {
        a = x + (j * dx4[i]);
        b = y + (j * dy4[i]);

        if (valid(h, w, a, b)) {
          if (v[a][b] != '@' and dp[a][b] > dp[x][y]) {
            if (dp[a][b] > (dp[x][y] + 1))
              dp[a][b] = dp[x][y] + 1, q.push({a, b});
          } else
            break;
        } else
          break;
      }
    }
  }
  if (dp[x2][y2] == (1LL << 32))
    dp[x2][y2] = -1;
  return dp[x2][y2];
}

int main() {
  IOS;
  lli x1, x2, y1, y2, i, j;

  cin >> h >> w >> k >> x1 >> y1 >> x2 >> y2;
  v.resize(h + 3);
  dp.resize(h + 3);

  rep(i, 1, h + 1) {
    v[i].resize(w + 3);
    dp[i].resize(w + 3);
    rep(j, 1, w + 1) { cin >> v[i][j]; }
  }

  initialize_dp(dp);
  dp[x1][y1] = 0;
  lli mini = bfs(x1, y1, x2, y2);

  cout << mini << endl;

  return 0;
}