Shift String by K Chunks

Medium

Write a function reorderString(s, k) that takes a string s and an integer k as input. The function should reorder the string s by reversing every consecutive block of k characters. If the number of remaining characters in the string is less than k, those characters should also be reversed. The function should return the reordered string.

For example: If s = "abcdefg" and k = 2:

The first block is "ab", reverse it to "ba".
The second block is "cd", reverse it to "dc".
The third block is "ef", reverse it to "fe".
The remaining block is "g" (less than k), reverse it to "g".
Concatenating these gives "badcfeg".

If s = "abcdefg" and k = 3:

The first block is "abc", reverse it to "cba".
The second block is "def", reverse it to "fed".
The remaining block is "g" (less than k), reverse it to "g".
Concatenating these gives "cbafedg".

Example 1

Input

[
  "abcdefg",
  "2"
]

Output

badcfeg

Explanation. Original string: "abcdefg", k = 2. Chunks: "ab" -> "ba", "cd" -> "dc", "ef" -> "fe", "g" -> "g". Result: "badcfeg".

Example 2

Input

[
  "abcdefg",
  "3"
]

Output

cbafedg

Explanation. Original string: "abcdefg", k = 3. Chunks: "abc" -> "cba", "def" -> "fed", "g" -> "g". Result: "cbafedg".

Example 3

Input

[
  "abcdefgh",
  "4"
]

Output

dcbahgfe

Explanation. Original string: "abcdefgh", k = 4. Chunks: "abcd" -> "dcba", "efgh" -> "hgfe". Result: "dcbahgfe".

Example 4

Input

[
  "abcde",
  "5"
]

Output

edcba

Explanation. Original string: "abcde", k = 5. Only one chunk: "abcde" -> "edcba". Result: "edcba".

Example 5

Input

[
  "abcde",
  "1"
]

Output

abcde

Explanation. Original string: "abcde", k = 1. Each character is a chunk and reversing a single character changes nothing. Result: "abcde".

Example 6

Input

[
  "a",
  "1"
]

Output

Explanation. Original string: "a", k = 1. One chunk "a" -> "a". Result: "a".

Example 7

Input

[
  "short",
  "10"
]

Output

trohs

Explanation. Original string: "short", k = 10. k is greater than the string length. The entire string "short" is treated as one block and reversed to "trohs". Result: "trohs".

Example 8

Input

[
  "programming",
  "4"
]

Output

rgorpimmgnra

Explanation. Original string: "programming", k = 4. Chunks: "prog" -> "gorp", "ramm" -> "mmar", "ing" -> "gni". Result: "gorp mmargni".

Follow-up: Can you solve this problem in-place if the string `s` was represented as a mutable character array?

Constraints:

- `1 <= s.length <= 1000` - `1 <= k` - `s` consists only of lowercase English letters.

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Shift String by K Chunks

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Shift String by K Chunks

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