400. Nth Digit 第N位

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:3Output:3

Example 2:

Input:11Output:0Explanation: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.

   

给定一个无穷整数序列1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, ... 求序列的第n位数字。

class Solution(object):
    def findNthDigit(self, n):
        """
        :type n: int
        :rtype: int
        """
        n -= 1
        for digits in range(1, 11):
            first = 10**(digits - 1)
            if n < 9 * first * digits:
                return int(str(first + n/digits)[n%digits])
            n -= 9 * first * digits

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