foo.cc: In function 'int main()':
foo.cc:9:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    9 |  for (int i=0;i<n.length();i++)
      |               ~^~~~~~~~~~~
foo.cc:12:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   12 |   for(int j=i+1;j<n.length();j++)
      |                 ~^~~~~~~~~~~

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