foo.cc: In function 'int main()':
foo.cc:76:81: warning: comparison of integer expressions of different signedness: 'unsigned int' and 'int' [-Wsign-compare]
   76 |             if ((kk ^ (tt ^ i)) == (a ^ i) && (a ^ i) < y && trie.xormax(a ^ i) <= n) y = (a ^ i);
      |                                                              ~~~~~~~~~~~~~~~~~~~^~~~

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