Language: C++

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pld pair<long double, int>
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pb push_back
#define ff first
#define ss second
#define SZ(x) ((int)(x).size())
#define ld long double
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const int MAXN = 1e3+100;
int H, W, x1, y1, x2, y2, D[MAXN][MAXN];
bool a[MAXN][MAXN], vis[MAXN][MAXN];

struct node{
    int x, y, d;
    bool operator<(const node &other) const{
        return d < other.d;
    }
};

bool valid(int x, int y){
    return (x >= 0 && x < H && y >= 0 && y < W && a[x][y]);
}

int dijkstra(){
    x1--, y1--, x2--, y2--;
    priority_queue<node> pq;
    pq.push({x1, y1, 0});
    D[x1][y1] = 0;
    while(!pq.empty()){
        int x = pq.top().x;
        int y = pq.top().y;
        int d = pq.top().d;
        pq.pop();
        if(vis[x][y])
            continue;
        vis[x][y] = true;
        for(int i = x-2; i <= x+2; i++){
            for(int j = y-2; j <= y+2; j++){
                if(!valid(i, j))
                    continue;
                if(i == x && j == y)
                    continue;
                if((i == x && abs(j - y) <= 1) || (j == y && abs(i - x) <= 1)){
                    if(D[i][j] > D[x][y]){
                        D[i][j] = D[x][y];
                        pq.push({i, j, D[i][j]});
                    }
                } else{
                    if(D[i][j] > D[x][y] + 1){
                        D[i][j] = D[x][y] + 1;
                        pq.push({i, j, D[i][j]});
                    }
                }
            }
        }
    }
    if(D[x2][y2] == INT_MAX)
        D[x2][y2] = -1;
    return D[x2][y2];
}

main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cin >> H >> W;
    cin >> x1 >> y1 >> x2 >> y2;
    for(int i = 0; i < H; i++){
        string s; cin >> s;
        for(int j = 0; j < W; j++){
            a[i][j] = (s[j] == '.');
            D[i][j] = INT_MAX;
        }
    }
    cout << dijkstra();
}


Compiler output:
a.cc:15:15: error: 'int y1' redeclared as different kind of entity
   15 | int H, W, x1, y1, x2, y2, D[MAXN][MAXN];
      |               ^~
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 dijkstra()':
a.cc:30:11: warning: ISO C++ forbids decrementing a pointer of type 'double (*)(double) noexcept' [-Wpointer-arith]
   30 |     x1--, y1--, x2--, y2--;
      |           ^~
a.cc:30:13: error: lvalue required as decrement operand
   30 |     x1--, y1--, x2--, y2--;
      |             ^~
a.cc:32:12: error: no matching function for call to 'std::priority_queue<node>::push(<brace-enclosed initializer list>)'
   32 |     pq.push({x1, y1, 0});
      |     ~~~~~~~^~~~~~~~~~~~~
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 = node; _Sequence = std::vector<node, std::allocator<node> >; _Compare = std::less<node>; value_type = node]'
  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<node>::value_type&' {aka 'const node&'}
  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 = node; _Sequence = std::vector<node, std::allocator<node> >; _Compare = std::less<node>; value_type = node]'
  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<node>::value_type&&' {aka 'node&&'}
  744 |       push(value_type&& __x)
      |            ~~~~~~~~~~~~~^~~
a.cc:33:10: error: invalid types 'int [1100][double(double) noexcept]' for array subscript
   33 |     D[x1][y1] = 0;
      |          ^
a.cc: At global scope:
a.cc:67:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   67 | main(){
      | ^~~~
a.cc: In function 'int main()':
a.cc:71:15: error: no match for 'operator>>' (operand types are 'std::basic_istream<char>::__istream_type' {aka 'std::basic_istream<char>'} and 'double(double) noexcept')
   71 |     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:71:18: error: cannot bind non-const lvalue reference of type 'bool&' to a value of type 'double (*)(double) noexcept'
   71 |     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:71:18: error: invalid conversion from 'double (*)(double) noexcept' to 'short int' [-fpermissive]
   71 |     cin >> x1 >> y1 >> x2 >> y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:71:18: 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:71:18: error: invalid conversion from 'double (*)(double) noexcept' to 'short unsigned int' [-fpermissive]
   71 |     cin >> x1 >> y1 >> x2 >> y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:71:18: 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:71:18: error: invalid conversion from 'double (*)(double) noexcept' to 'int' [-fpermissive]
   71 |     cin >> x1 >> y1 >> x2 >> y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:71:18: 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:71:18: error: invalid conversion from 'double (*)(double) noexcept' to 'unsigned int' [-fpermissive]
   71 |     cin >> x1 >> y1 >> x2 >> y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:71:18: 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:71:18: error: invalid conversion from 'double (*)(double) noexcept' to 'long int' [-fpermissive]
   71 |     cin >> x1 >> y1 >> x2 >> y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:71:18: 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:71:18: error: invalid conversion from 'double (*)(double) noexcept' to 'long unsigned int' [-fpermissive]
   71 |     cin >> x1 >> y1 >> x2 >> y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:71:18: 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:71:18: error: invalid conversion from 'double (*)(double) noexcept' to 'long long int' [-fpermissive]
   71 |     cin >> x1 >> y1 >> x2 >> y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:71:18: 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:71:18: error: invalid conversion from 'double (*)(double) noexcept' to 'long long unsigned int' [-fpermissive]
   71 |     cin >> x1 >> y1 >> x2 >> y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:71:18: 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>>