Function zigzag_path

utils/utils_zigzag.py:144–175

(N)

def zigzag_path(N):
    def zigzag_path_lr(N, start_row=0, start_col=0, dir_row=1, dir_col=1):
        path = []
        for i in range(N):
            for j in range(N):
                # If the row number is even, move right; otherwise, move left
                col = j if i % 2 == 0 else N - 1 - j
                path.append((start_row + dir_row * i) * N + start_col + dir_col * col)
        return path

    def zigzag_path_tb(N, start_row=0, start_col=0, dir_row=1, dir_col=1):
        path = []
        for j in range(N):
            for i in range(N):
                # If the column number is even, move down; otherwise, move up
                row = i if j % 2 == 0 else N - 1 - i
                path.append((start_row + dir_row * row) * N + start_col + dir_col * j)
        return path

    paths = []
    for start_row, start_col, dir_row, dir_col in [
        (0, 0, 1, 1),
        (0, N - 1, 1, -1),
        (N - 1, 0, -1, 1),
        (N - 1, N - 1, -1, -1),
    ]:
        paths.append(zigzag_path_lr(N, start_row, start_col, dir_row, dir_col))
        paths.append(zigzag_path_tb(N, start_row, start_col, dir_row, dir_col))

    for _index, _p in enumerate(paths):
        paths[_index] = np.array(_p)
    return paths


def rand_perm(N, num):