题解 | 字符串变形

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param s string字符串
     * @param n int整型
     * @return string字符串
     */
    public String trans (String s, int n) {
        int nums = 0;
        char[] charArray1 = s.toCharArray();

        for (int i = charArray1.length - 1; i >= 0; i--) {
            if (charArray1[i] == ' ') {
                nums++;
            } else {
                break;
            }
        }

        String[] split = s.split(" ");
        StringBuffer sb = new StringBuffer();

        for (int i = 0; i < nums; i++) {
            sb.append(" ");
        }
        if (split.length==0){
            return sb.toString();
        }
        for (int i = split.length - 1 ; i >= 0 ; i--) {
            String s1 = split[i];
            char[] charArray = s1.toCharArray();
            for (int j = 0 ; j < charArray.length  ; j++) {
                String c = charArray[j] + "";
                if (Character.isUpperCase(charArray[j])) {
                    sb.append(c.toLowerCase());
                } else {
                    sb.append(c.toUpperCase());
                }
            }
            sb.append(" ");
        }
        return sb.substring(0, sb.length() - 1);
    }
}