/in/foo.cc: In function 'void kruskal()':
/in/foo.cc:25:13: warning: array subscript is above array bounds [-Warray-bounds]
   q=find(a[i].from);
          ~~~^
/in/foo.cc:26:13: warning: array subscript is above array bounds [-Warray-bounds]
   p=find(a[i].to);
          ~~~^
/in/foo.cc:28:11: warning: array subscript is above array bounds [-Warray-bounds]
   sum+=a[i].wi;
        ~~~^
/in/foo.cc: In function 'int main()':
/in/foo.cc:44:33: warning: array subscript is above array bounds [-Warray-bounds]
   cin>>a[i].from>>a[i].to>>a[i].wi;
                                 ^~
/in/foo.cc:44:24: warning: array subscript is above array bounds [-Warray-bounds]
   cin>>a[i].from>>a[i].to>>a[i].wi;
                        ^~
/in/foo.cc:44:13: warning: array subscript is above array bounds [-Warray-bounds]
   cin>>a[i].from>>a[i].to>>a[i].wi;
             ^~~~
/in/foo.cc:45:11: warning: array subscript is above array bounds [-Warray-bounds]
   ans+=a[i].wi;
        ~~~^