[C++知识库]剑指offer java day03

T1 05. 替换空格

字符串 String 长度一定，StringBuilder动态长度

class Solution {
    public String replaceSpace(String s) {
        StringBuffer sb = new StringBuffer();
        for(char c:s.toCharArray()){
            if(c == ' '){
                sb.append("%20");
            }
            else{
                sb.append(c);
            }
        }
        return sb.toString();
    }
}

T2 58 - II. 左旋转字符串

class Solution {
    public String reverseLeftWords(String s, int n) {
        return s.substring(n)+s.substring(0,n);
    }
}