View Compilation Error

0_0_33214052_14798.cpp: In function 'int main()':
0_0_33214052_14798.cpp:37:60: error: 'update' was not declared in this scope
    if (i - 1 - d >= 1) update(1, a[i - 1 - d], f[i - 1 - d]);
                                                            ^