题目
给定一个字符串和一个偏移量，根据偏移量旋转字符串(从左向右旋转)
样例
对于字符串 "abcdefg".
offset=0 => "abcdefg"
offset=1 => "gabcdef"
offset=2 => "fgabcde"
offset=3 => "efgabcd"
分析
旋转字符串在原地旋转，利用了一个技巧，旋转三次可以达到效果，具体看代码分析即可。这种旋转的技巧需要熟练掌握
代码
public class Solution {
/**
* @param str: an array of char
* @param offset: an integer
* @return: nothing
*/
public void rotateString(char[] str, int offset) {
// write your code here
if (str == null || str.length == 0)
return;
offset = offset % str.length;
reverse(str, 0, str.length - offset - 1);
reverse(str, str.length - offset, str.length - 1);
reverse(str, 0, str.length - 1);
}
private void reverse(char[] str, int start, int end) {
for (int i = start, j = end; i < j; i++, j--) {
char temp = str[i];
str[i] = str[j];
str[j] = temp;
}
}
}
