转自wca规则：
E2d) The metric to measure the length of the solution, is Half Turn Metric.
Half Turn Metric (HTM) is defined as:
12a17) Each move of the categories Face Moves and Double Outer Slice Moves is counted as 1 move.
12a18) Each move of the categories Inner Slice Moves and Middle Slice Moves is counted as 2 moves.
12a19) Each rotation is counted as 0 moves.
Face Moves:
12a1) Clockwise, 90 degrees: F (front face), B (back face), R (right face), L (left face), U (upper face), D (bottom face).
12a2) Counter clockwise, 90 degrees: F', B', R', L', U', D' (see 12a1).
12a3) Clockwise, 180 degrees: F2, B2, R2, L2, U2, D2 (see 12a1).
12a4) Counter clockwise, 180 degrees: F2', B2', R2', L2', U2', D2' (see 12a1).