foo.cc: In function 'll calc(int, ll, ll)':
foo.cc:35:51: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
 inline ll calc(int u,ll s,ll h){return ch[u][1]?(s-h<<1):((a[u]<<1)>s?(s-a[u]<<1):s-1);}  //计算冲突值
                                                  ~^~
foo.cc:35:73: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
 inline ll calc(int u,ll s,ll h){return ch[u][1]?(s-h<<1):((a[u]<<1)>s?(s-a[u]<<1):s-1);}  //计算冲突值
                                                                        ~^~~~~
foo.cc: In function 'void rot(int)':
foo.cc:41:17: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
     if(ch[fa][d]=ch[o][d^1])f[ch[fa][d]]=fa;
        ~~~~~~~~~^~~~~~~~~~~
foo.cc: In function 'void work(int)':
foo.cc:61:34: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
     ans+=(maxn<<1)>sum[u]?(sum[u]-maxn<<1):sum[u]-1;
                            ~~~~~~^~~~~

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