transfer.cpp: In function 'std::vector<int> retrieve(std::vector<int>)':
transfer.cpp:30:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |  for (int i = 0; i < extra.size() - 1; i++) Xor ^= extra[i];
      |                  ~~^~~~~~~~~~~~~~~~~~
transfer.cpp:35:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   35 |   for (int j = 1; j <= data.size() - extra.size(); j++) {
      |                   ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
transfer.cpp:43:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   43 |  for (int i = 0; i < extra.size() - 1; i++) cur |= (1 << i) * extra[i];
      |                  ~~^~~~~~~~~~~~~~~~~~