题目
If the numbers 1 to 5 are written out in words: one, two, three, four, five, then there are 3+3+5+4+4=19 letters used in total.
If all the numbers from 1 to 1000 (one thousand) inclusive were written out in words, how many letters would be used?
NOTE: Do not count spaces or hyphens. For example, 342 (three hundred and forty-two) contains 23 letters and 115 (one hundred and fifteen) contains 20 letters. The use of “and” when writing out numbers is in compliance with British usage.
解答
首先是把数字对应的单词的长度记录一下，也就是下面代码里的n1, n10, n11和n这几个tupple。因为整个程序是只能算1000以内，所以加了句如果超出就报错的语句。然后我们就可以对数字进行拆解，再从这几个tupple里对应一个长度，加和一下，就可以把输入的数字转换成英文的字符串长度。
import sys
def nchar(x):
if (x > 1000):
print("x should be less than 1000...")
sys.exit(0)
n1=(0,3,3,5,4,4,3,5,5,4) # 1 to 9
n10=(0,3,6,6,5,5,5,7,6,6) # 10 to 90
n11=(0,6,6,8,8,7,7,9,8,8) # 11 to 19
n=(7,10,11) # hundred, hundred and, one thousand
if (x == 1000):
return n[2]
elif (x % 100 == 0):
return n1[x // 100] + n[0]
elif (x > 100):
y = x % 100
return n1[x // 100] + n[1] + nchar(x % 100)
elif (x < 10):
return n1[x]
elif (x == 10):
return n10[1]
elif (x >= 11and x <= 19):
return n11[x-10]
elif (x >= 20and x < 100):
return n10[x // 10] + n1[x % 10]
else:
return0
有了这个函数，那么就可以遍历需要计算的所有数，也是一个加和，就统计完成了。
def solution17(N):
res = 0
for i in range(1, N+1):
res += nchar(i)
return(res)
