In file included from /nix/store/wy4ywjsch9q2hj5lphqjdg9p2kf7w0ls-gcc-11.3.0/include/c++/11.3.0/cassert:44,
                 from foo.cc:20:
foo.cc: In function 'int query(int, int)':
foo.cc:154:42: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  154 |     assert(len[top]-(k-(dep[y]-dep[top]))<sav[top].size());
      |            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~

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