View Compilation Error

0_0_30467112_22550.cpp: In function 'void union_tree(int, int)':
0_0_30467112_22550.cpp:24:10: error: return-statement with a value, in function returning 'void' [-fpermissive]
   return 0;
          ^
0_0_30467112_22550.cpp:34:10: error: return-statement with a value, in function returning 'void' [-fpermissive]
   return 1;
          ^