View Compilation Error

0_0_20037690_3121.cpp: In function 'void calculate()':
0_0_20037690_3121.cpp:27:24: error: invalid operands of types 'int' and '<unresolved overloaded function type>' to binary 'operator!='
         while(front != end && nums[q[end - 1]] >= nums[i]) --end;
                        ^
0_0_20037690_3121.cpp:27:44: error: invalid operands of types '<unresolved overloaded function type>' and 'int' to binary 'operator-'
         while(front != end && nums[q[end - 1]] >= nums[i]) --end;
                                            ^
0_0_20037690_3121.cpp:27:62: error: no pre-decrement operator for type
         while(front != end && nums[q[end - 1]] >= nums[i]) --end;
                                                              ^
0_0_20037690_3121.cpp:28:14: error: no post-increment operator for type
         q[end++] = i;
              ^