/in/foo.cc: In function 'void build(int, int, int)':
/in/foo.cc:48:30: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  t[x].l=l,t[x].r=r; int mid=l+r>>1;
                             ~^~
/in/foo.cc:49:69: warning: narrowing conversion of 'l' from 'int' to 'DB {aka double}' inside { } [-Wnarrowing]
  if (l==r) return void(t[x]=(tree){a[l],b[l],a[l]*a[l],a[l]*b[l],l,r});
                                                                     ^
/in/foo.cc:49:69: warning: narrowing conversion of 'r' from 'int' to 'DB {aka double}' inside { } [-Wnarrowing]