/in/foo.cc: In function 'int kruskal()':
/in/foo.cc:37:6: warning: unused variable 's' [-Wunused-variable]
  int s=0,h=0,i,max=0;
      ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:60:8: warning: unused variable 'j' [-Wunused-variable]
  int i,j,k,a,b,c;
        ^
/in/foo.cc:60:10: warning: unused variable 'k' [-Wunused-variable]
  int i,j,k,a,b,c;
          ^