Interview problem #1

solution.py

from collections import OrderedDict, defaultdict


def add_tags(obj, string):
    # remember the index of each element
    indexes = {k: v for k, v in enumerate(string)}

    # formatting
    formatting = defaultdict(list)

    for k, v in obj.items():
        start, end = v

        if k == 'italics':
            style = 'i'
        elif k == 'bold':
            style = 'b'
        else:
            style = k

        for i in range(start, end + 1):
            formatting[i].append(style)

    # each index has a list of formats it should support, let's build anew string
    result = []

    for k, v in indexes.items():
        if k in formatting:
            result.extend([f"<{x}>" for x in formatting[k]])
            result.append(v)
            result.extend([f"</{x}>" for x in formatting[k][::-1]])
        else:
            result.append(v)

    print("".join(result))


add_tags({"bold": [0, 2], "italics": [1, 3]}, "ABCDE")