剑指 Offer 58 - II. 左旋转字符串

剑指 Offer 58 - II. 左旋转字符串

使用字符串分割再拼接

public class Solution {
    // 直接截取字符串拼接
    public String reverseLeftWords(String s, int n) {
        return s.substring(n) + s.substring(0, n);
    }
}

使用字符数组操作

class Solution {
    public String reverseLeftWords(String s, int n) {
        char[] chars = new char[s.length()];
        int index = 0;
        for (int i = n; i < s.length(); i++) {
            chars[index ++] = s.charAt(i);
        }
        for (int i = 0; i < n; i++) {
            chars[index ++] = s.charAt(i);
        }
        return new String(chars);
    }
}