View Compilation Error

0_0_25592009_7975.cpp:7:9: error: array bound is not an integer constant before ']' token
 } a[maxt];
         ^
0_0_25592009_7975.cpp: In function 'int main()':
0_0_25592009_7975.cpp:63:13: error: 'a' was not declared in this scope
             a[i].left=p1;
             ^
0_0_25592009_7975.cpp:67:14: error: 'a' was not declared in this scope
         sort(a+1,a+1+n,cmp);
              ^