foo.cc: In function 'std::vector<int> mul(std::vector<int>&, int)':
foo.cc:17:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   17 |     for(int i=0;i<A.size()||t;i++)
      |                 ~^~~~~~~~~
foo.cc:19:13: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   19 |         if(i<A.size()) t+=A[i]*b;
      |            ~^~~~~~~~~

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