Consider the infinite sequence of integers: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, ... Find the nth digit in the string where all numbers are placed one after another without spaces. Digits counting starts from 1.
findNthDigit(3) ➞ 3
// First digit of number 3
findNthDigit(10) ➞ 1
// First digit of number 10
findNthDigit(11) ➞ 0
// Second digit of number 10
findNthDigit(15) ➞ 2
// Second digit of number 12
1 <= n < 10^21