切割字符串拼接
左旋转字符串
http://www.nowcoder.com/questionTerminal/12d959b108cb42b1ab72cef4d36af5ec
public class Solution { public String LeftRotateString(String str,int n) { if (str == null || str.length() < 1) { return ""; } String pre = str.substring(0, n); String post = str.substring(n); return post + pre; } }