View Compilation Error

0_0_25732262_3022.cpp: In function 'void solve(int)':
0_0_25732262_3022.cpp:47:57: error: 'query' was not declared in this scope
     for (int i=1; i<=n; i++) ans^=1LL*i*query(1, 1, n, i);
                                                         ^