/in/foo.cc: In function 'int main()':
/in/foo.cc:29:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    if (p[b[i]] == v[b[i]].size()){
        ~~~~~~~~^~~~~~~~~~~~~~~~~
/in/foo.cc:22:12: warning: unused variable 'x' [-Wunused-variable]
   unsigned x = 0;
            ^