1的个数

# coding utf8# python3# 题目：1 的个数#   给定一个十进制整数 N，求出从 1 到 N 的所有整数中出现 “1” 的个数# 当 N=12 时，#   python num_of_1.py -N 12import sys, getoptdef sum_num(n):    if n == 0:        return 0    elif n < 10:        return 1    num = 0    c1 = 10    c2 = 1    a = int(n/c1)    b = n%c1    if b == 0:        num = num + a    else:        num = num + a + 1    while (a > 0):        c2 = c1        c1 = c1*10        a = int(n/c1)        b = int((n%c1)/c2)        c = (n%c1)%c2        if b == 0:            num = num + a*c2        elif b == 1:            num = num + a*c2 + c+1        else:            num = num + (a+1)*c2    return numif __name__ == "__main__":    opts, args = getopt.getopt(sys.argv[1:], "N:")    for op, value in opts:        if op == "-N":            n = int(value)            break    num = sum_num(n)    print("从 1 到 %d 的所有整数中出现 “1” 的个数为：%d" %(n, num))