adventofcode/2019/04a.py

# Python 3.7

def main():
    rangeStart = 109165
    rangeEnd = 576723
    count = 0
    for pw in range(rangeStart, rangeEnd):
        count += validatePassword(pw)
    print(count)

def validatePassword(pw):
    pwStr = str(pw)
    # does it have a doubled digit
    # does it have a descending digit
    c, d = 0, 0
    for i in range(1, len(pwStr)):
        if pwStr[i-1] == pwStr[i]:
            c = 1
        if int(pwStr[i]) < int(pwStr[i-1]):
            d = 1
    if c == 0 or d == 1:
        return 0
    return 1

if __name__ == "__main__":
    main()