reverse-string-ii

541. Reverse String II

LeetCode Problem Link

Difficulty: Easy

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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.

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Example 1

Input:

s = "abcdefg", k = 2

Output:

"bacdfeg"

Example 2

Input:

s = "abcd", k = 2

Output:

"bacd"

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Constraints

• $1 \leq s.\text{length} \leq 10^4$
• $s$ consists of only lowercase English letters.
• $1 \leq k \leq 10^4$