题解 | 无限长正整数排列字符串
无限长正整数排列字符串
https://www.nowcoder.com/practice/82c92d2321bb4220a3006d52a95a8bdd
n=int(input())
if n<=9:
print(n)
elif 9<n<189:
c=(n-9-1)//2
d=(n-9-1)%2
print(str(10+c)[d])
else:
c=(n-189-1)//3
d=(n-189-1)%3
print(str(100+c)[d])
