Problem	xmas
User	bribritt
Submission Time	2023-04-01 07:51:28
Score	0
Max Time	N/A
Max Memory	N/A

Compile Error

xmas.cpp: In member function ‘void node::update(int, int)’:
xmas.cpp:21:13: error: ‘f’ was not declared in this scope
21 | v = f(l->v, r->v);
| ^