/in/foo.cc: In function 'int main()':
/in/foo.cc:22:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < L + 1; i++)
                     ^
/in/foo.cc:27:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < n; i++)
                     ^
/in/foo.cc:30:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (int i = left; i <= right; i++)
                         ^
/in/foo.cc:46:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (int i = 22; i <= L; i++) 
                       ^
/in/foo.cc:60:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < ans.size(); i++)
                    ^