foo.cc: In function 'void perm(int*, int, int, int)':
foo.cc:28:8: warning: unused variable 's' [-Wunused-variable]
   28 |    int s=0;
      |        ^
foo.cc: In function 'int main()':
foo.cc:78:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   78 | for(int i=1;i<kk.size();i++)
      |             ~^~~~~~~~~~

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