View Compilation Error

0_0_39324208_30826.cpp: In function 'int main()':
0_0_39324208_30826.cpp:13:17: error: 'TreeArray' was not declared in this scope
   13 |                 TreeArray<32000>opt(32001);
      |                 ^~~~~~~~~
0_0_39324208_30826.cpp:13:33: error: 'opt' was not declared in this scope
   13 |                 TreeArray<32000>opt(32001);
      |                                 ^~~