Sword finger offer day 3 string (simple)

The finger of the sword Offer 05. Replace blank space https://leetcode-cn.com/problems/ti-huan-kong-ge-lcof/

class Solution {
    public String replaceSpace(String s) {
        String str = s.replace(" ", "%20");
        return str;
    }
}

 

The finger of the sword Offer 58 - II. Left rotation string https://leetcode-cn.com/problems/zuo-xuan-zhuan-zi-fu-chuan-lcof/

class Solution {
    public String reverseLeftWords(String s, int n) {
        String a = s.substring(0, n);
        //System.out.println(a);
        String b = s.substring(n, s.length());
        //System.out.println(b);
        String str = b + a;
        //System.out.println(s);
        return str;
    }
}