/in/foo.cc: In function 'void left(int)':
/in/foo.cc:43:8: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
     if (noroot(y))
        ^
/in/foo.cc:40:6: warning: unused variable 'flag' [-Wunused-variable]
  int flag; 
      ^~~~
/in/foo.cc: In function 'void right(int)':
/in/foo.cc:56:8: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
     if (noroot(y))
        ^
/in/foo.cc:53:6: warning: unused variable 'flag' [-Wunused-variable]
  int flag;
      ^~~~
/in/foo.cc: In function 'void splay(int)':
/in/foo.cc:83:5: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
  if (noroot(y))
     ^
/in/foo.cc:82:19: warning: unused variable 'k' [-Wunused-variable]
  int y=tree[x].fa,k=tree[y].fa;
                   ^
/in/foo.cc:73:6: warning: unused variable 'tot' [-Wunused-variable]
  int tot=0,y=x;
      ^~~