779. K-th Symbol in Grammar
Description
We build a table of n
rows (1-indexed). We start by writing 0
in the 1st
row. Now in every subsequent row, we look at the previous row and replace each occurrence of 0
with 01
, and each occurrence of 1
with 10
.
- For example, for
n = 3
, the1st
row is0
, the2nd
row is01
, and the3rd
row is0110
.
Given two integer n
and k
, return the kth
(1-indexed) symbol in the nth
row of a table of n
rows.
Example 1:
Input: n = 1, k = 1 Output: 0 Explanation: row 1: 0
Example 2:
Input: n = 2, k = 1 Output: 0 Explanation: row 1: 0 row 2: 01
Example 3:
Input: n = 2, k = 2 Output: 1 Explanation: row 1: 0 row 2: 01
Constraints:
1 <= n <= 30
1 <= k <= 2n - 1
Solutions
Solution 1
1 2 3 4 5 6 7 |
|
1 2 3 4 5 6 7 8 9 10 11 |
|
1 2 3 4 5 6 7 8 |
|
1 2 3 4 5 6 7 8 9 |
|
Solution 2
1 2 3 |
|
1 2 3 4 5 |
|
1 2 3 4 5 6 |
|
1 2 3 |
|