漢数字をアラビア数字へ変換する

KANJI_DIGITS = {
    "零": 0, "〇": 0,
    "一": 1, "二": 2, "三": 3, "四": 4, "五": 5,
    "六": 6, "七": 7, "八": 8, "九": 9,
}
KANJI_UNITS = {"十": 10, "百": 100, "千": 1000}
KANJI_BIG_UNITS = {"万": 10_000, "億": 100_000_000, "兆": 1_000_000_000_000}


def kanji_to_int(text: str) -> int:
    text = text.replace("約", "").replace("およそ", "")
    total = 0
    section = 0
    number = 0

    for ch in text:
        if ch in KANJI_DIGITS:
            number = KANJI_DIGITS[ch]
        elif ch in KANJI_UNITS:
            unit = KANJI_UNITS[ch]
            section += max(number, 1) * unit
            number = 0
        elif ch in KANJI_BIG_UNITS:
            unit = KANJI_BIG_UNITS[ch]
            section += number
            total += max(section, 1) * unit
            section = 0
            number = 0
        elif ch.isdigit():
            number = number * 10 + int(ch)
        else:
            continue

    return total + section + number


samples = ["三千五百二十円", "１２億３０００万", "4兆5000億", "約五万二千"]
for s in samples:
    print(s, "→", kanji_to_int(s))