/in/foo.cc: In function 'int main()':
/in/foo.cc:20:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(i=0;i<v1.size();i++)
          ~^~~~~~~~~~
/in/foo.cc:23:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j=0;j<v2.size();j++)
               ~^~~~~~~~~~
/in/foo.cc:23:3: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
   for(int j=0;j<v2.size();j++)
   ^~~
/in/foo.cc:26:4: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
    if(t==0)
    ^~
/in/foo.cc:29:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(i=0;i<v3.size();i++)
          ~^~~~~~~~~~