View Compilation Error

0_0_39628446_14111.cpp: In function 'int main()':
0_0_39628446_14111.cpp:29:34: error: 'lson' was not declared in this scope; did you mean 'ls'?
   29 |                         if(!idx) lson[i]=stk[1];
      |                                  ^~~~
      |                                  ls
0_0_39628446_14111.cpp:30:30: error: 'lson' was not declared in this scope; did you mean 'ls'?
   30 |                         else lson[i]=rson[stk[idx]],rson[stk[idx]]=i;
      |                              ^~~~
      |                              ls
0_0_39628446_14111.cpp:30:38: error: 'rson' was not declared in this scope; did you mean 'rs'?
   30 |                         else lson[i]=rson[stk[idx]],rson[stk[idx]]=i;
      |                                      ^~~~
      |                                      rs