from typing import List
from typing import Dict


def find_invariant_cols(results: List[List[str]]) -> Dict[int, str]:
    """
    This is particularly helpful with a small number of highly similar servers.

    :param results: list(table) of lists(rows) of cells
    :return: map of invariant indices (of columns) to their value.
    """
    invariant_values = []
    invariant_indices = []
    # Pre-populate on first row
    for cell in results[0]:
        invariant_values.append(cell)
        invariant_indices.append(True)
    for row in results[1:]:
        for i, cell in enumerate(row):
            if invariant_values[i] != cell:
                invariant_indices[i] = False
    return {i: kv[1] for i, kv in enumerate(zip(invariant_indices, invariant_values)) if kv[0]}