Language: C++

#include <bits/stdc++.h>

using namespace std;

#ifndef aa
#define trace(...)
#define endl '\n'
#endif
#define pb push_back
#define ub upper_bound
#define lb lower_bound
#define fi first
#define se second
#define int long long
typedef long long ll;
typedef long double ld;
#define double long double
#define pii pair<int,int>
#define pdd pair<double,double>
#define pll pair<ll,ll>
#define sz(x) ((long long)x.size())
#define fr(a,b,c) for(int a=b; a<=c; a++)
#define frev(a,b,c) for(int a=c; a>=b; a--)
#define rep(a,b,c) for(int a=b; a<c; a++)
#define trav(a,x) for(auto &a:x)
#define all(con) con.begin(),con.end()
#define deb(x) cout << x << endl
#define done(x) {cout << x << endl;return;}
const ll infl = 0x3f3f3f3f3f3f3f3fLL;
const int infi = 0x3f3f3f3f;
mt19937_64 mt(chrono::steady_clock::now().time_since_epoch().count());
//const int mod = 998244353;
const int mod = 1e9 + 7;
typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef vector<pair<int, int>> vpii;
typedef map<int, int> mii;
typedef set<int> si;
typedef set<pair<int,int>> spii;
typedef queue<int> qi;


const int N = 2e5+5;
int r,c,x1,x2,y1,y2;

bool f(int x, int y){
  return x>=0&&y>=0&&x<r&&y<c;
}

void solve() {

  
  cin>>r>>c>>x1>>y1>>x2>>y2;
  x1--,x2--,y1--,y2--;
  vvi a(r,vi(c));
  vvi d(r,vi(c,infl));
  rep(i,0,r){
    rep(j,0,c){
      char ch;
      cin>>ch;
      a[i][j]=(ch=='.');
    }
  }
  set<vi> pq;
  pq.insert({0,x2,y2});
  while(sz(pq)){
    vi v = *pq.begin();
    pq.erase(pq.begin());
    if(v[0]>=d[v[1]][v[2]])
      continue;
    d[v[1]][v[2]]=v[0];
    vi dx={0,0,1,-1}, dy={1,-1,0,0};
    rep(i,0,4){
      int x = v[1]+dx[i], y=v[2]+dy[i];
      if(f(x,y)&&a[x][y])
        pq.insert({v[0],x,y});
    }
    fr(del_x,-2,2){
      fr(del_y,-2,2){
        if(max(abs(del_x),abs(del_y))<2)
          continue;
        int x = v[1]+del_x, y=v[2]+del_y;
        if(f(x,y)&&a[x][y])
          pq.insert({v[0]+1,x,y});
      }
    }
  }
  int ans = d[x1][y1]==infl?-1:d[x1][y1];
  cout<<ans;
}


signed main() {
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    //srand(chrono::high_resolution_clock::now().time_since_epoch().count());
    cout << fixed << setprecision(15);
    int t = 1;
   //cin >> t;

    while (t--)
        solve();
#ifdef aa
    cout << endl << endl << endl << endl << "Time elapsed: " << (double)(clock() - clk) / CLOCKS_PER_SEC << endl;
#endif
    return 0;
}


int powm(int a, int b) {
    int res = 1;
    while (b) {
        if (b & 1)
            res = (res*a) % mod;
        a = (a * a) % mod;
        b >>= 1;
    }
    return res;
}


int divide(int a, int b) {
    return (a % mod) * powm(b, mod - 2) % mod;
}

int norm(int a) {
    while (a >= mod) a -= mod;
    while (a < 0) a += mod;
    return a;
}


int gcd(int a, int b) {
    return b ? gcd(b, a % b) : a;
}


Compiler output:
a.cc:44:15: error: 'long long int y1' redeclared as different kind of entity
   44 | int r,c,x1,x2,y1,y2;
      |               ^~
In file included from /usr/include/features.h:523,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/os_defines.h:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/c++config.h:683,
                 from /usr/include/c++/14/cassert:43,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:33,
                 from a.cc:1:
/usr/include/x86_64-linux-gnu/bits/mathcalls.h:257:1: note: previous declaration 'double y1(double)'
  257 | __MATHCALL (y1,, (_Mdouble_));
      | ^~~~~~~~~~
a.cc: In function 'void solve()':
a.cc:53:16: error: no match for 'operator>>' (operand types are 'std::basic_istream<char>::__istream_type' {aka 'std::basic_istream<char>'} and 'double(double) noexcept')
   53 |   cin>>r>>c>>x1>>y1>>x2>>y2;
      |   ~~~~~~~~~~~~~^~~~
      |            |     |
      |            |     double(double) noexcept
      |            std::basic_istream<char>::__istream_type {aka std::basic_istream<char>}
In file included from /usr/include/c++/14/sstream:40,
                 from /usr/include/c++/14/complex:45,
                 from /usr/include/c++/14/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:127:
/usr/include/c++/14/istream:170:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(bool&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  170 |       operator>>(bool& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:170:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:18: error: cannot bind non-const lvalue reference of type 'bool&' to a value of type 'double (*)(double) noexcept'
   53 |   cin>>r>>c>>x1>>y1>>x2>>y2;
      |                  ^~
/usr/include/c++/14/istream:174:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(short int&) [with _CharT = char; _Traits = std::char_traits<char>]' (near match)
  174 |       operator>>(short& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:174:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:18: error: invalid conversion from 'double (*)(double) noexcept' to 'short int' [-fpermissive]
   53 |   cin>>r>>c>>x1>>y1>>x2>>y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:53:18: error: cannot bind rvalue '(short int)y1' to 'short int&'
/usr/include/c++/14/istream:177:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(short unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  177 |       operator>>(unsigned short& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:177:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:18: error: invalid conversion from 'double (*)(double) noexcept' to 'short unsigned int' [-fpermissive]
   53 |   cin>>r>>c>>x1>>y1>>x2>>y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:53:18: error: cannot bind rvalue '(short unsigned int)y1' to 'short unsigned int&'
/usr/include/c++/14/istream:181:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(int&) [with _CharT = char; _Traits = std::char_traits<char>]' (near match)
  181 |       operator>>(int& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:181:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:18: error: invalid conversion from 'double (*)(double) noexcept' to 'int' [-fpermissive]
   53 |   cin>>r>>c>>x1>>y1>>x2>>y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:53:18: error: cannot bind rvalue '(int)y1' to 'int&'
/usr/include/c++/14/istream:184:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  184 |       operator>>(unsigned int& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:184:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:18: error: invalid conversion from 'double (*)(double) noexcept' to 'unsigned int' [-fpermissive]
   53 |   cin>>r>>c>>x1>>y1>>x2>>y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:53:18: error: cannot bind rvalue '(unsigned int)y1' to 'unsigned int&'
/usr/include/c++/14/istream:188:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  188 |       operator>>(long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:188:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:18: error: invalid conversion from 'double (*)(double) noexcept' to 'long int' [-fpermissive]
   53 |   cin>>r>>c>>x1>>y1>>x2>>y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:53:18: error: cannot bind rvalue '(long int)y1' to 'long int&'
/usr/include/c++/14/istream:192:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  192 |       operator>>(unsigned long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:192:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:18: error: invalid conversion from 'double (*)(double) noexcept' to 'long unsigned int' [-fpermissive]
   53 |   cin>>r>>c>>x1>>y1>>x2>>y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:53:18: error: cannot bind rvalue '(long unsigned int)y1' to 'long unsigned int&'
/usr/include/c++/14/istream:199:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  199 |       operator>>(long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:199:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:18: error: invalid conversion from 'double (*)(double) noexcept' to 'long long int' [-fpermissive]
   53 |   cin>>r>>c>>x1>>y1>>x2>>y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:53:18: error: cannot bind rvalue '(long long int)y1' to 'long long int&'
/usr/include/c++/14/istream:203:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  203 |       operator>>(unsigned long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:203:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:18: error: invalid conversion from 'double (*)(double) noexcept' to 'long long unsigned int' [-fpermissive]
   53 |   cin>>r>>c>>x1>>y1>>x2>>y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:53:18: error: cannot bind rvalue '(long long unsigned int)y1' to 'long long unsigned int&'
/usr/include/c++/14/istream:328:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(void*&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  328 |       operator>>(void*& __p)
      |       ^~~~~~~~
/usr/include/c++/14/istream:328:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:18: error: invalid conversion from 'double (*)(double) noexcept' to 'void*' [-fpermissive]
   53 |   cin>>r>>c>>x1>>y1>>x2>>y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:53:18: error: cannot bind rvalue '(void*)y1' to 'void*&'
/usr/include/c++/14/istream:122:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(__istream_type& (*)(__istream_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  122 |       operator>>(__istream_type& (*__pf)(__istream_type&))
      |       ^~~~~~~~
/usr/include/c++/14/istream:122:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:18: error: invalid conversion from 'double (*)(double) noexcept' to 'std::basic_istream<char>::__istream_type& (*)(std::basic_istream<char>::__istream_type&)' {aka 'std::basic_istream<char>& (*)(std::basic_istream<char>&)'} [-fpermissive]
   53 |   cin>>r>>c>>x1>>y1>>x2>>y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
/usr/include/c++/14/istream:126:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(__ios_type& (*)(__ios_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>; __ios_type = std::basic_ios<char>]' (near match)
  126 |       operator>>(__ios_type& (*__pf)(__ios_type&))
      |       ^~~~~~~~
/usr/include/c++/14/istream:126:7: note:   conversion of argument 1 would be ill-formed:
a.cc:53:18: error: invalid conversion from 'double (*)(double) noexcept' to 'std::basic_istream<char>::__ios_type& (*)(std::basic_istream<char>::__ios_type&)' {aka 'std::basic_ios<ch