foo.cc: In function ‘void build(int&, int, int)’:
foo.cc:84:19: warning: suggest parentheses around ‘+’ inside ‘>>’ [-Wparentheses]
   84 |         }int mid=l+r>>1;
      |                  ~^~
foo.cc: In function ‘void upd(int, int, mat, mat, int, int, int)’:
foo.cc:92:18: warning: suggest parentheses around ‘+’ inside ‘>>’ [-Wparentheses]
   92 |         int mid=l+r>>1;pushdown(x);
      |                 ~^~
foo.cc: In function ‘mat query(int, int, int, int, int)’:
foo.cc:100:18: warning: suggest parentheses around ‘+’ inside ‘>>’ [-Wparentheses]
  100 |         int mid=l+r>>1;pushdown(x);
      |                 ~^~