foo.cc: In function 'int main()':
foo.cc:45:26: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   45 |     for(int j=0;v2.size()<len;j++) {
      |                 ~~~~~~~~~^~~~
foo.cc:50:35: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   50 |     for(int j=v.size()-1;v1.size()<len;j--) {
      |                          ~~~~~~~~~^~~~
foo.cc:63:26: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   63 |     for(int j=0;v2.size()<len+1;j++) {
      |                 ~~~~~~~~~^~~~~~
foo.cc:68:35: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   68 |     for(int j=v.size()-1;v1.size()<len;j--) {
      |                          ~~~~~~~~~^~~~
foo.cc:34:7: warning: unused variable 'S' [-Wunused-variable]
   34 |   int S=v.size()-1;
      |       ^

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