/in/foo.cc: In function 'bool LCT::isroot(int)':
/in/foo.cc:54:56: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
 inline bool isroot(int x){return !f[x]||son[f[x]][0]!=x&&son[f[x]][1]!=x;}
                                         ~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~