View Compilation Error

0_0_37727493_23486.cpp: In function 'void init()':
0_0_37727493_23486.cpp:34:30: error: 'size' was not declared in this scope
     memset(head, 0, size(head));
                              ^
0_0_37727493_23486.cpp: In function 'void build(int, int, int)':
0_0_37727493_23486.cpp:53:42: error: 'size' was not declared in this scope
     memset(tree[rt].f, 0, size(tree[rt].f));
                                          ^