foo.cc: In member function 'void tree::add(int, int, int, ll)':
foo.cc:57:3: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   if (l<=m) add(p<<1,l,r,c);if (r>m) add(p<<1|1,l,r,c);
   ^~
foo.cc:57:29: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   if (l<=m) add(p<<1,l,r,c);if (r>m) add(p<<1|1,l,r,c);
                             ^~