/in/foo.cc:11:37: error: 'int y1 [110]' redeclared as different kind of symbol
 int n,dx[210],dy[210],x1[110],y1[110],x2[110],y2[110],f[210][210];
                                     ^
In file included from /usr/include/features.h:364:0,
                 from /usr/include/x86_64-linux-gnu/c++/6/bits/os_defines.h:39,
                 from /usr/include/x86_64-linux-gnu/c++/6/bits/c++config.h:507,
                 from /usr/include/c++/6/cassert:43,
                 from /usr/include/x86_64-linux-gnu/c++/6/bits/stdc++.h:33,
                 from /in/foo.cc:1:
/usr/include/x86_64-linux-gnu/bits/mathcalls.h:251:1: note: previous declaration 'double y1(double)'
 __MATHCALL (y1,, (_Mdouble_));
 ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:26:26: warning: pointer to a function used in arithmetic [-Wpointer-arith]
         x1[i]=read();y1[i]=read();x2[i]=read();y2[i]=read();
                          ^
/in/foo.cc:26:33: error: assignment of read-only location '*(y1 + ((sizetype)i))'
         x1[i]=read();y1[i]=read();x2[i]=read();y2[i]=read();
                                 ^
/in/foo.cc:26:33: error: cannot convert 'int' to 'double(double) throw ()' in assignment
/in/foo.cc:28:26: warning: pointer to a function used in arithmetic [-Wpointer-arith]
         cy.push_back(y1[i]);cy.push_back(y2[i]);
                          ^
/in/foo.cc:28:27: error: no matching function for call to 'push_back(double (&)(double) throw ())'
         cy.push_back(y1[i]);cy.push_back(y2[i]);
                           ^
In file included from /usr/include/c++/6/vector:64:0,
                 from /usr/include/c++/6/queue:61,
                 from /usr/include/x86_64-linux-gnu/c++/6/bits/stdc++.h:86,
                 from /in/foo.cc:1:
/usr/include/c++/6/bits/stl_vector.h:914:7: note: candidate: void std::vector<_Tp, _Alloc>::push_back(const value_type&) [with _Tp = int; _Alloc = std::allocator<int>; std::vector<_Tp, _Alloc>::value_type = int] <near match>
       push_back(const value_type& __x)
       ^~~~~~~~~
/usr/include/c++/6/bits/stl_vector.h:914:7: note:   conversion of argument 1 would be ill-formed:
/in/foo.cc:28:26: error: invalid conversion from 'double (*)(double) throw ()' to 'std::vector<int>::value_type {aka int}' [-fpermissive]
         cy.push_back(y1[i]);cy.push_back(y2[i]);
                      ~~~~^
In file included from /usr/include/c++/6/vector:64:0,
                 from /usr/include/c++/6/queue:61,
                 from /usr/include/x86_64-linux-gnu/c++/6/bits/stdc++.h:86,
                 from /in/foo.cc:1:
/usr/include/c++/6/bits/stl_vector.h:932:7: note: candidate: void std::vector<_Tp, _Alloc>::push_back(std::vector<_Tp, _Alloc>::value_type&&) [with _Tp = int; _Alloc = std::allocator<int>; std::vector<_Tp, _Alloc>::value_type = int] <near match>
       push_back(value_type&& __x)
       ^~~~~~~~~
/usr/include/c++/6/bits/stl_vector.h:932:7: note:   conversion of argument 1 would be ill-formed:
/in/foo.cc:28:26: error: invalid conversion from 'double (*)(double) throw ()' to 'std::vector<int>::value_type {aka int}' [-fpermissive]
         cy.push_back(y1[i]);cy.push_back(y2[i]);
                      ~~~~^
/in/foo.cc:39:61: warning: pointer to a function used in arithmetic [-Wpointer-arith]
         int tx1=findx(x1[i]),tx2=findx(x2[i]),ty1=findy(y1[i]),ty2=findy(y2[i]);
                                                             ^
/in/foo.cc:39:61: error: invalid conversion from 'double (*)(double) throw ()' to 'int' [-fpermissive]
         int tx1=findx(x1[i]),tx2=findx(x2[i]),ty1=findy(y1[i]),ty2=findy(y2[i]);
                                                         ~~~~^
/in/foo.cc:16:5: note:   initializing argument 1 of 'int findy(int)'
 int findy(int x){
     ^~~~~