一、题目内容

二、题解

解法1：

思路

模拟，拼接

代码

class Solution {
    public String reverseLeftWords(String s, int n) {
        char[] leftPrefix = new char[n];
        char[] ans = new char[s.length()];
        char[] chars = s.toCharArray();
        for (int i = 0; i < chars.length; i++) {
            if (i < n) {
                leftPrefix[i] = chars[i];
            } else {
                ans[i - n] = chars[i];
            }
        }
        for (int i = chars.length - n; i < chars.length; i++) {
            ans[i] = leftPrefix[i + leftPrefix.length - chars.length];
        }
        return new String(ans);
    }
}

解法2：

思路

取模

代码

class Solution {
    public String reverseLeftWords(String s, int n) {
        char[] ans = new char[s.length()];
        char[] chars = s.toCharArray();
        for (int i = n; i < chars.length + n; i++) {
            ans[i - n] = chars[i % chars.length];
        }
        return new String(ans);
    }
}