面试题：反转

在面试中出现频率比较高的一个题，如果不考虑效率的话，可以自己动手写一写。其实，系统的StringBuilder已经为我们提供了高效的字符串反转，感兴趣的同学可以看下StringBuilder.reverse()的实现。以下提供了几种实现方式，包括字符串反转和单词反转。

一、字符串反转

• 输入：Android Architecture Components
• 输出：stnenopmoC erutcetihcrA diordnA

String s = "Android Architecture Components";
StringBuilder sb = new StringBuilder(s);
Log.e("sunzn", String.valueOf(sb.reverse()));

二、字符串反转

• 输入：Android Architecture Components
• 输出：stnenopmoC erutcetihcrA diordnA

String s = "Android Architecture Components";
char[] chars = new char[s.length()];
for (int m = s.length() - 1, n = 0; m >= 0; m--, n++) {
    chars[n] = s.charAt(m);
}
s = String.copyValueOf(chars);
Log.e("sunzn", s);

三、单词反转

• 输入：Android Architecture Components
• 输出：Components Architecture Android

String s = "Android Architecture Components";
StringBuilder sb = new StringBuilder();
String[] split = s.split(" ");
for (int i = split.length - 1; i >= 0; i--) {
    sb.append(split[i]).append(i > 0 ? " " : "");
}
Log.e("sunzn", sb.toString());

赏

谢谢你请我吃糖果