Language: C++

    //For higher stack size use g++ -O2 -std=c++11 -Wall -Wl,--stack=268435456 a.cpp -o a.exe in cmd
    #include <bits/stdc++.h>
    #include <cstdio>
    #include <cstring>
    #include <cmath>
    #include <cstring>
    #include <chrono>
    #include <complex>
    #define ll long long
    #define ld long double
    #define vi vector<int>
    #define vll vector<ll>
    #define vvi vector < vi >
    #define pii pair<int,int>
    #define pll pair<long long, long long>
    #define mod 1000000007
    #define inf 1000000000000000001;
    #define all(c) c.begin(),c.end()
    #define mp(x,y) make_pair(x,y)
    #define mem(a,val) memset(a,val,sizeof(a))
    #define eb emplace_back
    #define pb push_back
    #define f first
    #define s second
    
    using namespace std;

    int dp[3001][3001],n,m;
    char ar[3001][3001];
    int x1,y1,x2,y2;

    bool chk(int x,int y,int z)
    {
        if(x<=0 || y<=0 || x>n || y>m || ar[x][y]=='#' || dp[x][y]<=z)
            return false;
        return true;
    }

    void bfs()
    {
        priority_queue<pair<int,pii>> pq;
        pq.push({0,{x1,y1}});
        dp[x1][y1]=0;
        pair<int,pii> x;
        while(!pq.empty())
        {
            x=pq.top();
            pq.pop();
            pii loc = x.s;
            int i=loc.f,j=loc.s;
            // cout<<i<<"..."<<j<<endl;
            if(dp[loc.f][loc.s]!=x.f)
                continue;
            if(chk(i-1,j,x.f))
            {
                dp[i-1][j]=x.f;
                pq.push({x.f,{i-1,j}});
            }
            if(chk(i+1,j,x.f))
            {
                dp[i+1][j]=x.f;
                pq.push({x.f,{i+1,j}});
            }
            if(chk(i,j-1,x.f))
            {
                dp[i][j-1]=x.f;
                pq.push({x.f,{i,j-1}});
            }
            if(chk(i,j+1,x.f))
            {
                dp[i][j+1]=x.f;
                pq.push({x.f,{i,j+1}});
            }
            for(int l=i-2;l<=i+2;++l)
            {
                for(int k=j-2;k<=j+2;++k)
                {
                    if(chk(l,k,x.f+1))
                    {
                        dp[l][k]=x.f+1;
                        pq.push({x.f+1,{l,k}});
                    }
                }
            }
        }
    }

    int main()
    {
        std::ios::sync_with_stdio(false);
        int T;
        T=1;
        // cin.ignore(); must be there when using getline(cin, s)
        while(T--)
        {
            int i,j;
            cin>>n>>m;
            cin>>x1>>y1>>x2>>y2;
            for(i=1;i<=n;++i)
            {
                for(j=1;j<=m;++j)
                {
                    cin>>ar[i][j];
                    dp[i][j]=1e9;
                }
            }
            bfs();
            if(dp[x2][y2]==1e9)
                dp[x2][y2]=-1;
            cout<<dp[x2][y2]<<endl;
        }
        return 0;
    }


Compiler output:
a.cc:30:12: error: 'int y1' redeclared as different kind of entity
   30 |     int x1,y1,x2,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:2:
/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 bfs()':
a.cc:42:16: error: no matching function for call to 'std::priority_queue<std::pair<int, std::pair<int, int> > >::push(<brace-enclosed initializer list>)'
   42 |         pq.push({0,{x1,y1}});
      |         ~~~~~~~^~~~~~~~~~~~~
In file included from /usr/include/c++/14/queue:66,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:157:
/usr/include/c++/14/bits/stl_queue.h:736:7: note: candidate: 'void std::priority_queue<_Tp, _Sequence, _Compare>::push(const value_type&) [with _Tp = std::pair<int, std::pair<int, int> >; _Sequence = std::vector<std::pair<int, std::pair<int, int> >, std::allocator<std::pair<int, std::pair<int, int> > > >; _Compare = std::less<std::pair<int, std::pair<int, int> > >; value_type = std::pair<int, std::pair<int, int> >]'
  736 |       push(const value_type& __x)
      |       ^~~~
/usr/include/c++/14/bits/stl_queue.h:736:30: note:   no known conversion for argument 1 from '<brace-enclosed initializer list>' to 'const std::priority_queue<std::pair<int, std::pair<int, int> > >::value_type&' {aka 'const std::pair<int, std::pair<int, int> >&'}
  736 |       push(const value_type& __x)
      |            ~~~~~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_queue.h:744:7: note: candidate: 'void std::priority_queue<_Tp, _Sequence, _Compare>::push(value_type&&) [with _Tp = std::pair<int, std::pair<int, int> >; _Sequence = std::vector<std::pair<int, std::pair<int, int> >, std::allocator<std::pair<int, std::pair<int, int> > > >; _Compare = std::less<std::pair<int, std::pair<int, int> > >; value_type = std::pair<int, std::pair<int, int> >]'
  744 |       push(value_type&& __x)
      |       ^~~~
/usr/include/c++/14/bits/stl_queue.h:744:25: note:   no known conversion for argument 1 from '<brace-enclosed initializer list>' to 'std::priority_queue<std::pair<int, std::pair<int, int> > >::value_type&&' {aka 'std::pair<int, std::pair<int, int> >&&'}
  744 |       push(value_type&& __x)
      |            ~~~~~~~~~~~~~^~~
a.cc:43:15: error: invalid types 'int [3001][double(double) noexcept]' for array subscript
   43 |         dp[x1][y1]=0;
      |               ^
a.cc: In function 'int main()':
a.cc:98:20: error: no match for 'operator>>' (operand types are 'std::basic_istream<char>::__istream_type' {aka 'std::basic_istream<char>'} and 'double(double) noexcept')
   98 |             cin>>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:98:22: error: cannot bind non-const lvalue reference of type 'bool&' to a value of type 'double (*)(double) noexcept'
   98 |             cin>>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:98:22: error: invalid conversion from 'double (*)(double) noexcept' to 'short int' [-fpermissive]
   98 |             cin>>x1>>y1>>x2>>y2;
      |                      ^~
      |                      |
      |                      double (*)(double) noexcept
a.cc:98:22: 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:98:22: error: invalid conversion from 'double (*)(double) noexcept' to 'short unsigned int' [-fpermissive]
   98 |             cin>>x1>>y1>>x2>>y2;
      |                      ^~
      |                      |
      |                      double (*)(double) noexcept
a.cc:98:22: 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:98:22: error: invalid conversion from 'double (*)(double) noexcept' to 'int' [-fpermissive]
   98 |             cin>>x1>>y1>>x2>>y2;
      |                      ^~
      |                      |
      |                      double (*)(double) noexcept
a.cc:98:22: 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:98:22: error: invalid conversion from 'double (*)(double) noexcept' to 'unsigned int' [-fpermissive]
   98 |             cin>>x1>>y1>>x2>>y2;
      |                      ^~
      |                      |
      |                      double (*)(double) noexcept
a.cc:98:22: 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:98:22: error: invalid conversion from 'double (*)(double) noexcept' to 'long int' [-fpermissive]
   98 |             cin>>x1>>y1>>x2>>y2;
      |                      ^~
      |                      |
      |                      double (*)(double) noexcept
a.cc:98:22: 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:98:22: error: invalid conversion from 'double (*)(double) noexcept' to 'long unsigned int' [-fpermissive]
   98 |             cin>>x1>>y1>>x2>>y2;
      |                      ^~
      |                      |
      |                      double (*)(double) noexcept
a.cc:98:22: 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:98:22: error: invalid conversion from 'double (*)(double) noexcept' to 'long long int' [-fpermissive]
   98 |             cin>>x1>>y1>>x2>>y2;
      |                      ^~
      |                      |
      |                      double (*)(double) noexcept
a.cc:98:22: 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:98:22: error: invalid conversion from 'double (*)(double) noexcept' to 'long long unsigned int' [-fpermissive]
   98 |             cin>>x1>>y1>>x2>>y2;
      |                      ^~
      |                      |
      |                      double (*)(double) noexcept
a.cc:98:22: error: cannot bind rvalue '(long long unsigned int)y1' to 'long long