View Compilation Error

0_0_39826842_7373.cpp: In function 'int main()':
0_0_39826842_7373.cpp:55:17: error: 'root2' was not declared in this scope
   55 |             pre[root2]=root1;
      |                 ^~~~~
0_0_39826842_7373.cpp:55:24: error: 'root1' was not declared in this scope
   55 |             pre[root2]=root1;
      |                        ^~~~~
0_0_39826842_7373.cpp: At global scope:
0_0_39826842_7373.cpp:66:1: error: expected declaration before '}' token
   66 | }
      | ^