用Java反转给定的句子

Question

有人能告诉我如何编写Java程序来逆转给定的句子吗？

例如，如果输入是：

“这是个面试问题”

产出必须是：

“问题面试是这样的吗”

Answer 1

您将字符串拆分为空格，然后向后迭代，以组装反转的句子。

String[] words =  "This is interview question".split(" ");

String rev = "";
for(int i = words.length - 1; i >= 0 ; i--)
{
   rev += words[i] + " ";
}

// rev = "question interview is This "

// can also use StringBuilder:
StringBuilder revb = new StringBuilder();
for(int i = words.length - 1; i >= 0 ; i--)
{
   revb.append(words[i]);
   revb.append(" ");
}
// revb.toString() = "question interview is This "

Answer 2

String[] words = sentence.split(" ");
String[] reversedWords = ArrayUtils.reverse(words);
String reversedSentence = StringUtils.join(reversedWords, " ");

(使用来自commons的ArrayUtils和StringUtils，但这些方法很容易编写-只有几个循环)

Answer 3

只是与众不同:一个递归的解决方案。不会增加任何额外的空间。

public static String reverse(String s) {
   int k = s.indexOf(" ");
   return k == -1 ? s : reverse(s.substring(k + 1)) + " " + s.substring(0, k);
}


System.out.println("[" + reverse("This is interview question") + "]");
// prints "[question interview is This]"

我还将通过使用split来改进\b解决方案(这太明显了！)

    String[] parts = "Word boundary is better than space".split("\\b");
    StringBuilder sb = new StringBuilder();
    for (int i = parts.length; i --> 0 ;) {
        sb.append(parts[i]);
    }
    System.out.println("[" + sb.toString() + "]");
    // prints "[space than better is boundary Word]"