S=123456789101112131415161718192021…
Given that the string S is the concatenation of the first 1,000,000,000 positive integers in ascending order, find the 999999999th digit of S.
Details and Assumptions:
By the xth digit of S, we mean the digit in the xth place from the left in the decimal representation of S.
Some explicit examples are :
- The 5th digit of the number 14583469 is 3.
- The 4th digit of the number 143256 is 2.