[LeetCode] 400. Nth Digit

轉自LeetCode

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.

<Solution>

想法如下(參考資料)

• 第一步，先確定答案會在哪個區間。是在雙位數還是三位數

• 第二步，找到答案所在的數字

• 第三步，找到哪一個位數是所要的答案

code 如下

C++