Language: C++

#include <bits/stdc++.h>
#define endl '\n'
#define fast ios::sync_with_stdio(0),cin.tie(0),cout.tie(0)
#define zy -2147382637
#define bql 2147483647
#define ll long long
#define ull unsigned long long
#define ld long double
#define il inline
#define sz(x) x.size()
#define maxn 100010
#define rp(i, l, r) for (int i = l; i <= r; i++)
#define rb(i, r, l) for (int i = r; i >= l; i--)
#define fi first
#define se second
#define pb push_back
#define mp make_pair

using namespace std;
ll max(ll a,ll b){if(a>b)return a;else return b;}
ll min(ll a,ll b){if(a<b)return a;else return b;}
ll lowbit(ll x){return x&(-x);}
ll prime(ll x){
   if(x<=1)return false;
   for(int i=2;i<=int(sqrt(x));i++){
	   if(x%i==0)return false;
   }return true;
}bool cmp(ll a,ll b){return a>b;}
ll gcd(ll a,ll b){ll r;while(b>0){r=a%b;a=b;b=r;}return a;}
ll powmod(ll a,ll b,ll mod) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
inline int readint() {
	char c = getchar(); int w = 1; int x = 0;
	while (!isdigit(c))
		(c == '-') && (w = -w), c = getchar();
	while (isdigit(c))
		x = (x << 3) + (x << 1) + (c ^ '0'), c = getchar();
	x *= w;
	return x;
}
inline ll readll() {
	char c = getchar(); ll w = 1; ll x = 0;
	while (!isdigit(c))
		(c == '-') && (w = -w), c = getchar();
	while (isdigit(c))
		x = (x << 3) + (x << 1) + (c ^ '0'), c = getchar();
	x *= w;
	return x;
}
void fl(string name){
	freopen((name+".in").c_str(),"r",stdin);
	freopen((name+".out").c_str(),"w",stdout);
}
const int dx[8] = {-1, 1, 0, 0, -1, 1, -1, 1},
		  dy[8] = {0, 0, -1, 1, -1, -1, 1, 1};
struct node{int x,y;};
int h,w,k,x1,y1,x2,y2;
bool ok(int x,int y){
	if(x<=h&&x>=1&&y<=w&&y>=1)return true;
	else return false;
}
queue<node>Q;
int main(){
	cin>>h>>w>>k;
	char g[h+1][w+1];
	int vis[h+1][w+1],step[h+1][w+1];
	memset(vis,0,sizeof(vis));
	memset(step,0,sizeof(step));
	cin>>x1>>y1>>x2>>y2;
	for(int i=1;i<=h;i++){
		for(int j=1;j<=w;j++){
			cin>>g[i][j];
		}
	}
	node a,b;
	a.x=x1,a.y=y1;
	step[x1][y1]=0;
	vis[x1][y1]=1;
	Q.push(a);
	int ans=bql;
	while(!Q.empty()){
		a=Q.front();
		Q.pop();
		if(a.x==x2&&a.y==y2){
			ans=min(ans,step[x2][y2]);
		}
		for(int i=0;i<4;i++){
			for(int j=1;j<=k;j++){
				b.x=dx[i]*j+a.x;
				b.y=dy[i]*j+a.y;
				if(ok(b.x,b.y)==0||(step[b.x][b.y]<=step[a.x][a.y]&&step[b.x][b.y]))break;
				else{
					if(g[b.x][b.y]=='@')break;
					if(g[b.x][b.y]=='.'&&!vis[b.x][b.y]){
						vis[b.x][b.y]=1;
						step[b.x][b.y]=step[a.x][a.y]+1;
						Q.push(b);
					}
				}
			}
		}
	}
	if(ans==bql)cout<<-1<<endl;
	else cout<<ans<<endl;
	return 0;
}
/* stuff to remember
	* int overflow, array bounds
	* special cases (n=1? n=0?)
	* do something instead of nothing and stay organized
	* USE STATIC ARRAYS
	* DEFINING ARRAYS BEFORE main()
	* DO NOT DEFINE ARRAYS IN main()
	* USE INT INSTEAD OF LL,NOTICE THE MLE
*/

Compiler output:
a.cc:56:14: error: 'int y1' redeclared as different kind of entity
   56 | int h,w,k,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: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:68:16: error: no match for 'operator>>' (operand types are 'std::basic_istream<char>::__istream_type' {aka 'std::basic_istream<char>'} and 'double(double) noexcept')
   68 |         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:68:18: error: cannot bind non-const lvalue reference of type 'bool&' to a value of type 'double (*)(double) noexcept'
   68 |         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:68:18: error: invalid conversion from 'double (*)(double) noexcept' to 'short int' [-fpermissive]
   68 |         cin>>x1>>y1>>x2>>y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:68:18: 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:68:18: error: invalid conversion from 'double (*)(double) noexcept' to 'short unsigned int' [-fpermissive]
   68 |         cin>>x1>>y1>>x2>>y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:68:18: 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:68:18: error: invalid conversion from 'double (*)(double) noexcept' to 'int' [-fpermissive]
   68 |         cin>>x1>>y1>>x2>>y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:68:18: 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:68:18: error: invalid conversion from 'double (*)(double) noexcept' to 'unsigned int' [-fpermissive]
   68 |         cin>>x1>>y1>>x2>>y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:68:18: 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:68:18: error: invalid conversion from 'double (*)(double) noexcept' to 'long int' [-fpermissive]
   68 |         cin>>x1>>y1>>x2>>y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:68:18: 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:68:18: error: invalid conversion from 'double (*)(double) noexcept' to 'long unsigned int' [-fpermissive]
   68 |         cin>>x1>>y1>>x2>>y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:68:18: 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:68:18: error: invalid conversion from 'double (*)(double) noexcept' to 'long long int' [-fpermissive]
   68 |         cin>>x1>>y1>>x2>>y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:68:18: 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:68:18: error: invalid conversion from 'double (*)(double) noexcept' to 'long long unsigned int' [-fpermissive]
   68 |         cin>>x1>>y1>>x2>>y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:68:18: 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:68:18: error: invalid conversion from 'double (*)(double) noexcept' to 'void*' [-fpermissive]
   68 |         cin>>x1>>y1>>x2>>y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:68:18: 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:68:18: 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]
   68 |         cin>>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:68:18: error: invalid conversion from 'double (*)(double) noexcept' to 'std::basic_istream<char>::__ios_type& (*)(std::basic_istream<char>::__ios_type&)' {aka 'std::basic_ios<char>& (*)(st