/in/foo.cc: In function 'bool pd(std::vector<rect>)':
/in/foo.cc:37:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=1; i<r.size(); i++)
              ~^~~~~~~~~
/in/foo.cc:36:12: warning: unused variable 'j' [-Wunused-variable]
     int i, j;
            ^
/in/foo.cc: In function 'void dfs1(int, int)':
/in/foo.cc:128:12: warning: unused variable 'j' [-Wunused-variable]
     int i, j;
            ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:179:12: warning: unused variable 'j' [-Wunused-variable]
     int i, j;
            ^