foo.cc: In function 'std::vector<long long int> mul(std::vector<long long int>&, long long int)':
foo.cc:21:9: error: could not convert 'c' from 'std::vector<int>' to 'std::vector<long long int>'
  return c;
         ^
foo.cc: In function 'int main()':
foo.cc:115:22: warning: format '%d' expects argument of type 'int', but argument 2 has type '__gnu_cxx::__alloc_traits<std::allocator<long long int> >::value_type {aka long long int}' [-Wformat=]
    printf("%d",res[i]);
                      ^
foo.cc:119:23: warning: format '%d' expects argument of type 'int', but argument 2 has type '__gnu_cxx::__alloc_traits<std::allocator<long long int> >::value_type {aka long long int}' [-Wformat=]
    printf("%d",ans1[i]);
                       ^
foo.cc:29:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%d",&n,&m,&k);
  ~~~~~^~~~~~~~~~~~~~~~~~~

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