Python, Straightforward with Explanation
For every block of 2k characters starting with position i, we want to replace S[i:i+k] with it's reverse.\n\ndef reverseStr(self, s, k):\n    s = list(s)\n    f
For every block of 2k characters starting with position i, we want to replace S[i:i+k] with it's reverse.\n```\ndef reverseStr(self, s, k):\n    s = list(s)\n    for i in xrange(0, len(s), 2*k):\n        s[i:i+k] = reversed(s[i:i+k])\n    return "".join(s)\n```
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