View Compilation Error

0_0_28004372_11919.cpp:6:1: error: expected ',' or ';' before 'int'
 int pre[maxn];
 ^
0_0_28004372_11919.cpp: In function 'void init()':
0_0_28004372_11919.cpp:20:5: error: 'pre' was not declared in this scope
     pre[i]=i;
     ^
0_0_28004372_11919.cpp: In function 'int find(int)':
0_0_28004372_11919.cpp:27:8: error: 'pre' was not declared in this scope
  while(pre[r]!=r)
        ^
0_0_28004372_11919.cpp: In function 'void join(int, int)':
0_0_28004372_11919.cpp:35:3: error: 'pre' was not declared in this scope
   pre[fx]=fy;
   ^