View Compilation Error

0_0_37312144_15690.cpp:5:15: error: size of array 'fa' is not an integral constant-expression
 int n,m,k,fa[N],cnt,cas,sum;
               ^
0_0_37312144_15690.cpp: In function 'int Kruskal(int)':
0_0_37312144_15690.cpp:84:19: error: 'struct node' has no member named 'a'
   int A=Find(x[i].a);
                   ^
0_0_37312144_15690.cpp:85:19: error: 'struct node' has no member named 'b'
   int B=Find(x[i].b);
                   ^