/in/foo.cc: In function 'void build(int&, int, int)':
/in/foo.cc:40:9: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int m=l+r>>1;
        ~^~
/in/foo.cc: In function 'void rotate(int)':
/in/foo.cc:53:2: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  if(c) fa[c]=f; ch[f][b]=c;
  ^~
/in/foo.cc:53:17: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'
  if(c) fa[c]=f; ch[f][b]=c;
                 ^~
/in/foo.cc: In function 'void splay(int, int)':
/in/foo.cc:61:3: warning: this 'else' clause does not guard... [-Wmisleading-indentation]
   else rotate(p);rotate(p);
   ^~~~
/in/foo.cc:61:18: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'else'
   else rotate(p);rotate(p);
                  ^~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:109:11: warning: unused variable 'j' [-Wunused-variable]
     int i,j,k;
           ^
/in/foo.cc:109:13: warning: unused variable 'k' [-Wunused-variable]
     int i,j,k;
             ^