foo.cc: In function 'void Output(std::vector<int>&)':
foo.cc:5:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0; i<v.size(); i++)
                  ~^~~~~~~~~
foo.cc: In function 'void FindAsc(std::vector<int>&, std::vector<int>&)':
foo.cc:27:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<v.size();i++)
                 ~^~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:48:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0; i+2<si1.size(); i+=2)
              ~~~^~~~~~~~~~~
foo.cc:51:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0; i+2<si2.size(); i+=2)
              ~~~^~~~~~~~~~~
foo.cc:39:25: warning: 'n1' is used uninitialized in this function [-Wuninitialized]
     vector<int> v1(a1,a1+n1);
                       ~~^~~
foo.cc:41:25: warning: 'n2' may be used uninitialized in this function [-Wmaybe-uninitialized]
     vector<int> v2(a2,a2+n2);
                       ~~^~~

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