Given a string s and an integer k, reverse the first k characters for every 2k characters counting from the start of the string.
If there are fewer than k characters left, reverse all of them. If there are less than 2k but greater than or equal to k characters, then reverse the first k characters and leave the other as original.
Examples
Example 1
Input: s = "abcdefg", k = 2
Output: "bacdfeg"
Example 2
Input: s = "abcd", k = 2
Output: "bacd"
Constraints
1 <= s.length <= 104
s consists of only lowercase English letters.
1 <= k <= 104
541. Reverse String II
Easy
10 Points
Two Pointers
String
Given a string s and an integer k, reverse the first k characters for every 2k characters counting from the start of the string.
If there are fewer than k characters left, reverse all of them. If there are less than 2k but greater than or equal to k characters, then reverse the first k characters and leave the other as original.