【剑指Offer 42】翻转单词顺序

题目：输入一个英文句子，翻转句子中单词的顺序，但单词内字啊的顺序不变。为简单起见，标点符号和普通字母一样处理。

代码如下：

package demo;

/**
 * 翻转单词顺序
 * 
 * @author xiangdonglee
 *
 */
public class Test42_1 {
    /**
     * 将data中start到end之间的字符翻转
     * 
     * @param data
     * @param start
     * @param end
     */
    public static void reverse(char[] data, int start, int end) {
        if (data == null || data.length < 1 || start < 0 || end > data.length || start > end) {
            return;
        }
        while (start < end) {
            char tmp = data[start];
            data[start] = data[end];
            data[end] = tmp;
            start++;
            end--;
        }
    }

    /**
     * 翻转句子中单词的顺序，但单词内字符顺序不变
     * 
     * @param data
     * @return
     */
    public static char[] reverseSentence(char[] data) {
        if (data == null || data.length < 1) {
            return data;
        }
        reverse(data, 0, data.length - 1);
        int start = 0;
        int end = 0;
        while (start < data.length) {
            if (data[start] == ' ') {
                start++;
                end++;
            } else if (end == data.length || data[end] == ' ') {
                reverse(data, start, end - 1);
                end++;
                start = end;
            } else {
                end++;
            }
        }
        return data;
    }

    public static void main(String[] args) {
        test1();
    }

    private static void test1() {
        System.out.println(new String(reverseSentence("I am a student.".toCharArray())));
        System.out.println(new String(reverseSentence("Wonderful".toCharArray())));
        System.out.println(new String(reverseSentence("".toCharArray())));
        System.out.println(new String(reverseSentence("  ".toCharArray())));
    }
}

来源：http://blog.csdn.net/derrantcm/article/details/46784471