Nxnxn Rubik: 39scube Algorithm Github Python Verified

Introduction: Beyond the 3x3 For decades, the 3x3 Rubik's Cube has been the poster child for combinatorial puzzles. However, for serious programmers, speedcubing theorists, and puzzle enthusiasts, the ultimate challenge is the NxNxN Rubik's Cube —a cube of any size, from the humble 2x2 to the monstrous 33x33 (the largest ever manufactured).

Every stage's move set is proven to reduce the cube to the next subgroup (G1 → G2 → G3 → solved). The code checks that after each phase, the cube belongs to the correct subgroup using invariant scanning. Writing Your Own Verified NxNxN Solver: A Step-by-Step Template If you can't find the perfect repo, here's how to build a verified NxNxN solver in Python, using ideas from the verified projects above. Step 1: Data Structure Represent the cube as a dictionary of (N, N, N) positions to colors. Use numpy for performance. nxnxn rubik 39scube algorithm github python verified

def R(self, layer=0): """Rotate the right face. layer=0 is the outermost slice.""" # Rotate the R face self.state['R'] = np.rot90(self.state['R'], k=-1) # Cycle the adjacent faces (U, F, D, B) for the given layer # ... implementation ... self._verify_invariants() def _verify_invariants(self): # 1. All pieces have exactly one sticker of each color? No — central pieces. # Instead, check that total permutation parity is even. # Simplified: count each color; should equal n*n for each face's primary color. for face, color in zip(['U','D','F','B','L','R'], ['U','D','F','B','L','R']): count = np.sum(self.state[face] == color) assert count == self.n * self.n, f"Invariant failed: Face {face} has {count} of {color}" For full verification, implement reduction and test each phase: Introduction: Beyond the 3x3 For decades, the 3x3

from nxnxn import Cube c = Cube(4) # 4x4 c.move("R U R' U'") # Sextet assert c.is_verified() # Checks all cubies are valid The code checks that after each phase, the

This project focuses on rather than solving speed. It models the cube as a group of permutations, allowing formal verification of move sequences.

from rubikscubennnsolver.RubiksCubeNNNEven import RubiksCubeNNNEven from rubikscubennnsolver.RubiksCubeNNNOdd import RubiksCubeNNNOdd cube = RubiksCubeNNNOdd(5, 'URFDLB') cube.randomize() cube.solve() assert cube.solved()