Example:
Input: s = "abcdefg", k = 2
Output: "bacdfeg"
Restrictions:
public class Solution {
public String reverse(String s) {
if (s == null || s.length() == 0) {
return null;
}
char[] chars = s.toCharArray();
int length = chars.length;
int start = 0, end = length - 1;
while (start < end) {
char tmp = chars[start];
chars[start++] = chars[end];
chars[end--] = tmp;
}
String result = "";
for (char c : chars)
result += c;
return result;
}
public String reverseStr(String s, int k) {
if (null == s || s.length() == 0)
return null;
int length = s.length();
int one = 1;
int count = length % k == 0 ? length / k : length / k + 1;
String result = "";
for (int i = 1; i <= count; i++) {
if (one % 2 == 1)
result += reverse(s.substring(k * (i -1), (k * i > length ? length : k * i)));
else
result += s.substring(k * (i -1), (k * i > length ? length : k * i));
one++;
}
return result;
}
}
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