/in/foo.cc: In function 'void dfsl(int)':
/in/foo.cc:20:11: warning: unused variable 'k' [-Wunused-variable]
   int i,j,k,A=a[x],B=b[x];
           ^
/in/foo.cc: In function 'void dfsr(int, int)':
/in/foo.cc:31:11: warning: unused variable 'k' [-Wunused-variable]
   int i,j,k,A=a[x],B=b[x];
           ^