View Compilation Error

0_0_6288293_19532.cpp: In function `void update(int, int, int)':
0_0_6288293_19532.cpp:30: error: `tree' undeclared (first use this function)
0_0_6288293_19532.cpp:30: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_6288293_19532.cpp: In function `int query(int, int, int)':
0_0_6288293_19532.cpp:45: error: 'struct Node' has no member named 'mid'
0_0_6288293_19532.cpp:47: error: 'struct Node' has no member named 'mid'
0_0_6288293_19532.cpp:53: error: 'struct Node' has no member named 'mid'
0_0_6288293_19532.cpp:53: error: 'struct Node' has no member named 'mid'