View Compilation Error

0_0_36123472_28744.cpp: In function 'int ZL::Solve(int)':
0_0_36123472_28744.cpp:19:5: error: 'tn' was not declared in this scope
     tn = root = n;
     ^
0_0_36123472_28744.cpp:19:10: error: 'root' was not declared in this scope
     tn = root = n;
          ^