Language: C++

#include<bits/stdc++.h>
using namespace std;

const int N = 1e6 + 5;
typedef long long LL;

int h, w, k, a[N], f[N], x, y, x1, y1;
int dx[5] = {0, 1, 0, 0, -1};
int dy[5] = {0, 0, 1, -1, 0};
struct node {
	int r, c;
} q[N<<2];

int p(int x, int y) { return (x - 1)*w + y; }

int Bfs() {
	memset(f, 0x7f, sizeof(f));
	f[p(x, y)] = 0;
	int l = 1, r = 1;
	q[l] = (node) {x, y};
	while(l <= r) {
		int x = q[l].r, y = q[l].c;
		if(x == x1 && y == y1) return f[p(x, y)];
		for(int i = 1; i <= 4; i++) {
			int nx = x, ny = y;
			for(int j = 1; j <= k; j++) {
				nx += dx[i], ny += dy[i];
				if(nx > h || nx < 1 || ny < 1 || ny > w) break;
				if(a[p(nx, ny)]) break;
				if(f[p(nx, ny)] <= f[p(x, y)]) break;
				f[p(nx, ny)] = f[p(x, y)] + 1;
				q[++r] = (node) {nx, ny};
			} 
		}
		l++;
	}
	return -1;
}

int main() {
	cin>>h>>w>>k>>x>>y>>x1>>y1;
	for(int i = 1; i <= h; i++)
		for(int j = 1; j <= w; j++) {
			char ch;
			cin>>ch;
			if(ch != '.') a[p(i, j)] = 1;
		}
	cout<<Bfs()<<endl;
	return 0;
}

Compiler output:
a.cc:7:36: error: 'int y1' redeclared as different kind of entity
    7 | int h, w, k, a[N], f[N], x, y, x1, y1;
      |                                    ^~
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 Bfs()':
a.cc:23:33: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
   23 |                 if(x == x1 && y == y1) return f[p(x, y)];
      |                               ~~^~~~~
a.cc: In function 'int main()':
a.cc:41:31: error: no match for 'operator>>' (operand types are 'std::basic_istream<char>::__istream_type' {aka 'std::basic_istream<char>'} and 'double(double) noexcept')
   41 |         cin>>h>>w>>k>>x>>y>>x1>>y1;
      |         ~~~~~~~~~~~~~~~~~~~~~~^~~~
      |                           |     |
      |                           |     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:41:33: error: cannot bind non-const lvalue reference of type 'bool&' to a value of type 'double (*)(double) noexcept'
   41 |         cin>>h>>w>>k>>x>>y>>x1>>y1;
      |                                 ^~
/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:41:33: error: invalid conversion from 'double (*)(double) noexcept' to 'short int' [-fpermissive]
   41 |         cin>>h>>w>>k>>x>>y>>x1>>y1;
      |                                 ^~
      |                                 |
      |                                 double (*)(double) noexcept
a.cc:41:33: 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:41:33: error: invalid conversion from 'double (*)(double) noexcept' to 'short unsigned int' [-fpermissive]
   41 |         cin>>h>>w>>k>>x>>y>>x1>>y1;
      |                                 ^~
      |                                 |
      |                                 double (*)(double) noexcept
a.cc:41:33: 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:41:33: error: invalid conversion from 'double (*)(double) noexcept' to 'int' [-fpermissive]
   41 |         cin>>h>>w>>k>>x>>y>>x1>>y1;
      |                                 ^~
      |                                 |
      |                                 double (*)(double) noexcept
a.cc:41:33: 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:41:33: error: invalid conversion from 'double (*)(double) noexcept' to 'unsigned int' [-fpermissive]
   41 |         cin>>h>>w>>k>>x>>y>>x1>>y1;
      |                                 ^~
      |                                 |
      |                                 double (*)(double) noexcept
a.cc:41:33: 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:41:33: error: invalid conversion from 'double (*)(double) noexcept' to 'long int' [-fpermissive]
   41 |         cin>>h>>w>>k>>x>>y>>x1>>y1;
      |                                 ^~
      |                                 |
      |                                 double (*)(double) noexcept
a.cc:41:33: 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:41:33: error: invalid conversion from 'double (*)(double) noexcept' to 'long unsigned int' [-fpermissive]
   41 |         cin>>h>>w>>k>>x>>y>>x1>>y1;
      |                                 ^~
      |                                 |
      |                                 double (*)(double) noexcept
a.cc:41:33: 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:41:33: error: invalid conversion from 'double (*)(double) noexcept' to 'long long int' [-fpermissive]
   41 |         cin>>h>>w>>k>>x>>y>>x1>>y1;
      |                                 ^~
      |                                 |
      |                                 double (*)(double) noexcept
a.cc:41:33: 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:41:33: error: invalid conversion from 'double (*)(double) noexcept' to 'long long unsigned int' [-fpermissive]
   41 |         cin>>h>>w>>k>>x>>y>>x1>>y1;
      |                                 ^~
      |                                 |
      |                                 double (*)(double) noexcept
a.cc:41:33: 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:41:33: error: invalid conversion from 'double (*)(double) noexcept' to 'void*' [-fpermissive]
   41 |         cin>>h>>w>>k>>x>>y>>x1>>y1;
      |                                 ^~
      |                                 |
      |                                 double (*)(double) noexcept
a.cc:41:33: 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:41:33: 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]
   41 |