Language: C++

#include<bits/stdc++.h>
using namespace std;
#define r(i,n) for(int i=0;i<n;i++)
typedef double D;
typedef complex<D> P;
typedef pair<P, P> L;
typedef vector<P> VP;
const D EPS = 1e-9;
#define X real()
#define Y imag()
D dot(P a,P b) {return (conj(a)*b).X; }
D cross(P a,P b) {return(conj(a)*b).Y;}
int ccw(P a,P b,P c){
  b-=a;c-=a;
  if(cross(b,c)>EPS)return +1;
  if(cross(b,c)< -EPS)return -1;
  if(dot(b,c)< -EPS)return +2;
  if(norm(b)<norm(c))return -2;
  return 0;
}
bool isecSS(P a1, P a2, P b1, P b2) {
  return ccw(a1, a2, b1)*ccw(a1, a2, b2) <= 0 &&
         ccw(b1, b2, a1)*ccw(b1, b2, a2) <= 0;
}
bool isecSP(P a1,P a2,P b) {return !ccw(a1,a2,b);}
P proj(P a1,P a2,P p){return a1+dot(a2-a1, p-a1)/norm(a2-a1)*(a2-a1);}
D distSP(P a1,P a2,P p) {
  P r=proj(a1,a2,p);
  if(isecSP(a1,a2,r))return abs(r-p);
  return min(abs(a1-p),abs(a2-p));
}

D distSS(P a1,P a2,P b1,P b2) {
  if (isecSS(a1,a2,b1,b2))return 0;
  return min(min(distSP(a1,a2,b1),distSP(a1,a2,b2)),min(distSP(b1,b2,a1),distSP(b1,b2,a2)));
}
int n,x;
double h,x1,y1,a[222][222];
vector<P>v[222];
main(){
  while(cin>>h>>n,h+n){
    r(i,222)r(j,222)a[i][j]=1e9;
    r(i,222)v[i].clear();
    v[0].push_back(P(0,0));
    v[0].push_back(P(0,1e9));
    v[n+1].push_back(P(h,0));
    v[n+1].push_back(P(h,1e9));
    r(i,n){
      cin>>x;
      while(x--){
        cin>>x1>>y1;
        v[i+1].push_back(P(x1,y1));
      }
    }
    r(i,n+2)r(j,n+2)r(k,v[i].size()-1)
      r(l,v[j].size()-1)a[i][j]=min(a[i][j],distSS( v[i][k] , v[i][(k+1)%((int)v[i].size())] ,v[j][l] , v[j] [(l+1)%((int)v[j].size())] ));
    r(k,n+2)r(i,n+2)r(j,n+2)a[i][j]=min(a[i][j],a[i][k]+a[k][j]);
    printf("%.9f\n",a[0][n+1]);
  }
}

Compiler output:
a.cc:38:13: error: 'double y1' redeclared as different kind of entity
   38 | double h,x1,y1,a[222][222];
      |             ^~
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:40:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   40 | main(){
      | ^~~~
a.cc: In function 'int main()':
a.cc:51:16: error: no match for 'operator>>' (operand types are 'std::basic_istream<char>::__istream_type' {aka 'std::basic_istream<char>'} and 'double(double) noexcept')
   51 |         cin>>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:51:18: error: cannot bind non-const lvalue reference of type 'bool&' to a value of type 'double (*)(double) noexcept'
   51 |         cin>>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:51:18: error: invalid conversion from 'double (*)(double) noexcept' to 'short int' [-fpermissive]
   51 |         cin>>x1>>y1;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:51:18: 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:51:18: error: invalid conversion from 'double (*)(double) noexcept' to 'short unsigned int' [-fpermissive]
   51 |         cin>>x1>>y1;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:51:18: 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:51:18: error: invalid conversion from 'double (*)(double) noexcept' to 'int' [-fpermissive]
   51 |         cin>>x1>>y1;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:51:18: 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:51:18: error: invalid conversion from 'double (*)(double) noexcept' to 'unsigned int' [-fpermissive]
   51 |         cin>>x1>>y1;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:51:18: 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:51:18: error: invalid conversion from 'double (*)(double) noexcept' to 'long int' [-fpermissive]
   51 |         cin>>x1>>y1;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:51:18: 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:51:18: error: invalid conversion from 'double (*)(double) noexcept' to 'long unsigned int' [-fpermissive]
   51 |         cin>>x1>>y1;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:51:18: 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:51:18: error: invalid conversion from 'double (*)(double) noexcept' to 'long long int' [-fpermissive]
   51 |         cin>>x1>>y1;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:51:18: 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:51:18: error: invalid conversion from 'double (*)(double) noexcept' to 'long long unsigned int' [-fpermissive]
   51 |         cin>>x1>>y1;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:51:18: 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:51:18: error: invalid conversion from 'double (*)(double) noexcept' to 'void*' [-fpermissive]
   51 |         cin>>x1>>y1;
      |                  ^~
      |                  |
      |                  double (*)(double) noexcept
a.cc:51:18: 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:51:18: 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]
   51 |         cin>>x1>>y1;
      |                  ^~
      |                  |
      |                  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:51:18: error: invalid conversion from 'double (*)(double) noexcept' to 'std::basic_istream<char>::__ios_type& (*)(std::basic_istream<char>::__ios_type&)' {aka 's