/in/foo.cc: In function 'int main()':
/in/foo.cc:11:22: error: '__gnu_cxx::__alloc_traits<std::allocator<xpy>, xpy>::value_type' {aka 'struct xpy'} has no member named 'push_back'
   11 |                 a[i].push_back(xpy{x,y,z});
      |                      ^~~~~~~~~
/in/foo.cc: In lambda function:
/in/foo.cc:13:76: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   13 |         sort(a.begin(),a.end(),[](xpy x,xpy y){return x.yw>y.yw||x.yw==y.yw&&x.sx>y.sx;});
      |                                                                  ~~~~~~~~~~^~~~~~~~~~~