import hashlib

# PART 1


def chars(start, amount):
    n = 0
    chars = []
    while amount > 0:
        text = (start + str(n)).encode("utf-8")
        h = hashlib.md5(text).hexdigest()
        if h[:5] == "00000":
            # print(h, "->", char)
            char = h[5]
            chars.append(char)
            amount -= 1
        n += 1
    return "".join(chars)


# PART 2


def chars_2(start, amount):
    n = 0
    chars = [None] * amount
    while amount > 0:
        text = (start + str(n)).encode("utf-8")
        h = hashlib.md5(text).hexdigest()
        if h[:5] == "00000":
            char = h[6]
            pos = int(h[5], base=16)
            if pos < len(chars):
                if chars[pos] is None:
                    chars[pos] = char
                    pw = "".join("_" if x is None else x for x in chars)
                    # print(h, "->", char, "in position", pos, "->", pw)
                    if None not in chars:
                        return "".join(chars)
                # else:
                #     print(h, "->", chars[pos], "already in position", pos)
            # else:
            #     print(h, "->", "invalid position", pos)
        n += 1


def solve(inputstr):
    hashstart = inputstr.strip()
    pw = chars(hashstart, 8)
    print(f"Part 1: {pw}")
    pw_2 = chars_2(hashstart, 8)
    print(f"Part 2: {pw_2}")