View Compilation Error

0_0_37767579_5873.cpp: In function 'int querry_tree(int, int, int, int, int)':
0_0_37767579_5873.cpp:57:42: error: '_node' was not declared in this scope
   int maxn_right=querry_tree(mid+1, end, _node, L, R);
                                          ^