/in/foo.cc: In function 'int main()':
/in/foo.cc:9:2: error: 'vector' was not declared in this scope
  vector<int> a(n);
  ^~~~~~
/in/foo.cc:9:9: error: expected primary-expression before 'int'
  vector<int> a(n);
         ^~~
/in/foo.cc:10:9: error: expected primary-expression before 'int'
  vector<int> b(n);
         ^~~
/in/foo.cc:13:8: error: 'a' was not declared in this scope
   cin>>a[i]>>b[i];
        ^
/in/foo.cc:13:14: error: 'b' was not declared in this scope
   cin>>a[i]>>b[i];
              ^
/in/foo.cc:17:10: error: 'b' was not declared in this scope
   if(max(b[i+1],a[i]*b[i])>max(b[i],a[i+1]*b[i+1]))
          ^
/in/foo.cc:17:17: error: 'a' was not declared in this scope
   if(max(b[i+1],a[i]*b[i])>max(b[i],a[i+1]*b[i+1]))
                 ^
/in/foo.cc:30:13: error: 'b' was not declared in this scope
   int c = s/b[i];
             ^
/in/foo.cc:32:6: error: 'a' was not declared in this scope
   s*=a[i];
      ^