Language: C++

#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
#include <map>
#include <deque>
#include <queue>
#include <string>
#include <string.h>
#include <math.h>
#include <iomanip>
#include <stdio.h>
using namespace std;

#define int64 long long
#define pii pair <int, int>
#define fr first
#define sc second
#define heap priority_queue
struct piii{
    int64 fr, sc, th;
    bool operator < (const piii &b){
        if (fr != b.fr) return fr < b.fr;
        if (sc != b.sc) return sc < b.sc;
        return th < b.th;
    }
};
///////////////////////////////////////////////
///////////////////////////////////////////////

const int oo = 1e9;
int m, n, k, x1, y1, x2, y2;
vector <vector <pii>> pn, ps, pw, pe;
vector <vector <int>> f;
vector <vector <bool>> dd;
vector <string> s;
queue <pii> qu;


void init(vector <vector <pii>> &a){
    a.resize(m + 2);
    for (int i = 0; i <= m + 1; i++)
        a[i].resize(n + 2);
}

void init(vector <vector <bool>> &a){
    a.resize(m + 2);
    for (int i = 0; i <= m + 1; i++)
        a[i].resize(n + 2, false);
}

void init(vector <vector <int>> &a){
    a.resize(m + 2);
    for (int i = 0; i <= m + 1; i++)
        a[i].resize(n + 2, oo);
}

pii getp(vector <vector <pii>> &p, pii u){
    pii tmp = p[u.fr][u.sc];
    if (tmp.fr >= 0 && tmp.fr < m && tmp.sc >= 0 && tmp.sc < n && dd[tmp.fr][tmp.sc])
        p[u.fr][u.sc] = getp(p, tmp);
    return p[u.fr][u.sc];
}

void go(vector <vector <pii>> &p, pii u, int val){
    while (1){
        u = getp(p, u);
        if (u.fr < 0 || u.fr >= m || u.sc < 0 || u.sc >= n || s[u.fr][u.sc] == '@')
            return;
        dd[u.fr][u.sc] = true;
        f[u.fr][u.sc] = val + 1;
        qu.push(u);
    }
}

int main(){
    cout << setprecision(2) << fixed;
    ios::sync_with_stdio(false), cin.tie(0);
    //freopen("input.txt", "r", stdin);
    cin >> m >> n >> k;
    cin >> x1 >> y1 >> x2 >> y2;
    x1--, x2--, y1--, y2--;
    s.resize(m + 2);
    init(pn);
    init(ps);
    init(pw);
    init(pe);
    init(f);
    init(dd);
    for (int i = 0; i < m; i++)
        cin >> s[i];
    for (int i = 0; i < m; i++)
    for (int j = 0; j < n; j++){
        //if (s[i][j] == '@') dd[i][j] = true;
        pn[i][j] = {i - 1, j};
        ps[i][j] = {i + 1, j};
        pw[i][j] = {i, j - 1};
        pe[i][j] = {i, j + 1};
    }
    /*
    for (int i = 0; i <= m + 1; i++)
        dd[i][0] = dd[i][n + 1] = true;
    for (int i = 0; i <= n + 1; i++)
        dd[0][i] = dd[m + 1][i] = true;
    */
    f[x1][y1] = 0;
    qu.push(pii({x1, y1}));
    while (!qu.empty()){
        pii cur = qu.front();
        //cout << cur.fr << ' ' << cur.sc << ' ' << f[cur.fr][cur.sc] << endl;
        if (cur.fr == x2 && cur.sc == y2){
            cout << f[x2][y2] + 1;
            exit (0);
        }
        qu.pop();
        go(pn, cur, f[cur.fr][cur.sc]);
        go(ps, cur, f[cur.fr][cur.sc]);
        go(pw, cur, f[cur.fr][cur.sc]);
        go(pe, cur, f[cur.fr][cur.sc]);
    }
    cout << -1;
    return 0;
}


Compiler output:
a.cc:32:18: error: 'int y1' redeclared as different kind of entity
   32 | int m, n, 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/bits/requires_hosted.h:31,
                 from /usr/include/c++/14/iostream:38,
                 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:81:15: error: no match for 'operator>>' (operand types are 'std::basic_istream<char>::__istream_type' {aka 'std::basic_istream<char>'} and 'double(double) noexcept')
   81 |     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/iostream:42:
/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:81:18: error: cannot bind non-const lvalue reference of type 'bool&' to a value of type 'double (*)(double) noexcept'
   81 |     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:81:18: error: invalid conversion from 'double (*)(double) noexcept' to 'short int' [-fpermissive]
   81 |     cin >> x1 >> y1 >> x2 >> y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:81:18: 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:81:18: error: invalid conversion from 'double (*)(double) noexcept' to 'short unsigned int' [-fpermissive]
   81 |     cin >> x1 >> y1 >> x2 >> y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:81:18: 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:81:18: error: invalid conversion from 'double (*)(double) noexcept' to 'int' [-fpermissive]
   81 |     cin >> x1 >> y1 >> x2 >> y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:81:18: 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:81:18: error: invalid conversion from 'double (*)(double) noexcept' to 'unsigned int' [-fpermissive]
   81 |     cin >> x1 >> y1 >> x2 >> y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:81:18: 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:81:18: error: invalid conversion from 'double (*)(double) noexcept' to 'long int' [-fpermissive]
   81 |     cin >> x1 >> y1 >> x2 >> y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:81:18: 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:81:18: error: invalid conversion from 'double (*)(double) noexcept' to 'long unsigned int' [-fpermissive]
   81 |     cin >> x1 >> y1 >> x2 >> y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:81:18: 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:81:18: error: invalid conversion from 'double (*)(double) noexcept' to 'long long int' [-fpermissive]
   81 |     cin >> x1 >> y1 >> x2 >> y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:81:18: 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:81:18: error: invalid conversion from 'double (*)(double) noexcept' to 'long long unsigned int' [-fpermissive]
   81 |     cin >> x1 >> y1 >> x2 >> y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:81:18: 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:81:18: error: invalid conversion from 'double (*)(double) noexcept' to 'void*' [-fpermissive]
   81 |     cin >> x1 >> y1 >> x2 >> y2;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:81:18: 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:81:18: 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]
   81 |     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:81:18: 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>& (*)(std::basic_ios<char>&)'} [-fpermissive]
   81 |     cin >> x1 >> y1 >> x2 >> y2;
      |                  ^~
      |                  |