Language: C++

#include<bits/stdc++.h>
#define pii pair<int,int>
#define mp make_pair
using namespace std;

const int maxH = 1e3, maxW = 1e3;
const int oo = 1e9 + 7;

int H, W, x1, x2, y1, y2;
bool path[maxH][maxW], mark[maxH][maxW];
int f[maxH][maxW];

int xx[4] = {0, 1, 0, -1};
int yy[4] = {1, 0, -1, 0};

priority_queue<pii, vector<pii>, greater<pii>> q;

int node(const int& a, const int& b)
{
    return a * H + b;
}
int main()
{
    cin >> H >> W >> x1 >> y1 >> x2 >> y2;
    --x1;   --x2;   --y1;   --y2;
    for (int i = 0; i < H; ++i)
        for (int j = 0; j < W; ++j)
        {
            char c;     cin >> c;
            if (c == '.') path[i][j] = 1;
            f[i][j] = oo;
        }
    q.push(mp(0, x1 * H + y1));
    f[x1][y1] = 0;
    while (!q.empty())
    {
        int u = q.top().second;
        int w = q.top().first;
        q.pop();
        int x = u / H, y = u % H;
        if (mark[x][y]) continue;
        else mark[x][y] = 1;
        if (x == x2 && y == y2) break;
        for (int p = 0; p < 4; ++p)
        {
            int nx = x + xx[p], ny = y + yy[p];
            if (nx < 0 || ny < 0) continue;
            if (!path[nx][ny]) continue;
            if (mark[nx][ny]) continue;
            if (f[nx][ny] > f[x][y])
            {
                f[nx][ny] = f[x][y];
                q.push(mp(f[nx][ny], node(nx, ny)));
            }
        }
        for (int i = -2; i <= 2; ++i)
            for (int j = -2; j <= 2; ++j)
            {
                int nx = x + i, ny = y + j;
                if (nx < 0 || ny < 0) continue;
                if (!path[nx][ny]) continue;
                if (mark[nx][ny]) continue;
                if (f[nx][ny] > f[x][y] + 1)
                {
                    f[nx][ny] = f[x][y] + 1;
                    q.push(mp(f[nx][ny], node(nx, ny)));
                }
            }
    }
    if (f[x2][y2] == oo) f[x2][y2] = -1;
    cout << f[x2][y2];
  
  	return 0;
}


Compiler output:
a.cc:9:19: error: 'int y1' redeclared as different kind of entity
    9 | int H, W, 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 'int main()':
a.cc:24:25: error: no match for 'operator>>' (operand types are 'std::basic_istream<char>::__istream_type' {aka 'std::basic_istream<char>'} and 'double(double) noexcept')
   24 |     cin >> H >> W >> 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:24:28: error: cannot bind non-const lvalue reference of type 'bool&' to a value of type 'double (*)(double) noexcept'
   24 |     cin >> H >> W >> 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:24:28: error: invalid conversion from 'double (*)(double) noexcept' to 'short int' [-fpermissive]
   24 |     cin >> H >> W >> x1 >> y1 >> x2 >> y2;
      |                            ^~
      |                            |
      |                            double (*)(double) noexcept
a.cc:24:28: 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:24:28: error: invalid conversion from 'double (*)(double) noexcept' to 'short unsigned int' [-fpermissive]
   24 |     cin >> H >> W >> x1 >> y1 >> x2 >> y2;
      |                            ^~
      |                            |
      |                            double (*)(double) noexcept
a.cc:24:28: 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:24:28: error: invalid conversion from 'double (*)(double) noexcept' to 'int' [-fpermissive]
   24 |     cin >> H >> W >> x1 >> y1 >> x2 >> y2;
      |                            ^~
      |                            |
      |                            double (*)(double) noexcept
a.cc:24:28: 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:24:28: error: invalid conversion from 'double (*)(double) noexcept' to 'unsigned int' [-fpermissive]
   24 |     cin >> H >> W >> x1 >> y1 >> x2 >> y2;
      |                            ^~
      |                            |
      |                            double (*)(double) noexcept
a.cc:24:28: 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:24:28: error: invalid conversion from 'double (*)(double) noexcept' to 'long int' [-fpermissive]
   24 |     cin >> H >> W >> x1 >> y1 >> x2 >> y2;
      |                            ^~
      |                            |
      |                            double (*)(double) noexcept
a.cc:24:28: 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:24:28: error: invalid conversion from 'double (*)(double) noexcept' to 'long unsigned int' [-fpermissive]
   24 |     cin >> H >> W >> x1 >> y1 >> x2 >> y2;
      |                            ^~
      |                            |
      |                            double (*)(double) noexcept
a.cc:24:28: 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:24:28: error: invalid conversion from 'double (*)(double) noexcept' to 'long long int' [-fpermissive]
   24 |     cin >> H >> W >> x1 >> y1 >> x2 >> y2;
      |                            ^~
      |                            |
      |                            double (*)(double) noexcept
a.cc:24:28: 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:24:28: error: invalid conversion from 'double (*)(double) noexcept' to 'long long unsigned int' [-fpermissive]
   24 |     cin >> H >> W >> x1 >> y1 >> x2 >> y2;
      |                            ^~
      |                            |
      |                            double (*)(double) noexcept
a.cc:24:28: 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:24:28: error: invalid conversion from 'double (*)(double) noexcept' to 'void*' [-fpermissive]
   24 |     cin >> H >> W >> x1 >> y1 >> x2 >> y2;
      |                            ^~
      |                            |
      |                            double (*)(double) noexcept
a.cc:24:28: 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:24:28: 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]
   24 |     cin >> H >> W >> 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& (*)(__i