Problem Description
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.
Key Insights
- The problem requires reversing segments of the string based on the value of k.
- The string is processed in chunks of 2k, where the first k characters are reversed and the next k characters remain unchanged.
- Special cases need to be handled when the remaining characters are fewer than k or between k and 2k.
Space and Time Complexity
Time Complexity: O(n), where n is the length of the string s. Each character is processed once. Space Complexity: O(n), for the storage of the resulting string (if using a new string for the output).
Solution
To solve the problem, we can use a straightforward approach by iterating over the string in increments of 2k. For each 2k segment, we reverse the first k characters using slicing, then concatenate the resultant string with the next segment of characters. This is done until we have processed the entire string.