lc400. Nth DigitFind the nth digit of the infinite integer s

Nth Digit Easy

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Share Find the nth digit of the infinite integer sequence 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, ...

Note: n is positive and will fit within the range of a 32-bit signed integer (n < 231).

Example 1:

Input: 3

Output: 3 Example 2:

Input: 11

Output: 0

Explanation: The 11th digit of the sequence 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, ... is a 0, which is part of the number 10.

思路：1-9 10-99 100-999 分别个数为9，90，900，所以，可以查找出数字位数，位置

代码：python3

class Solution:
    def findNthDigit(self, n: int) -> int:
        le = 1
        count = 9
        start = 1
        while n>le*count:
            n -= le*count
            le += 1
            count *= 10
            start *= 10
        
        start += (n-1)/le
        return int(str(start)[(n-1)%le])