557. Reverse Words in a String III 难度：简单

Given a string, you need to reverse the order of characters in each word within a sentence while still preserving whitespace and initial word order.

Example 1:

Input: "Let's take LeetCode contest"Output: "s'teL ekat edoCteeL tsetnoc"

Note: In the string, each word is separated by single space and there will not be any extra space in the string.

算法分析：找到一个空格，然后把之前的字符串翻转。

C语言版

这里有一点比较有趣，如果把求字符串长度strlen(s)不声明变量，每次循环都调用就会超时，以前还真没遇到过，以后需要注意。

char* reverseWords(char* s) {    int i, j, start = 0, end;    int len = strlen(s);    for(i = 0, j = 0; i <= len; i++)    {        int t;        if(s[i] == ' ' || i == len)        {            end = i - 1;            for(j = start; j <= (start + end) / 2; j++)            {                char temp = s[j];                s[j] = s[start + end -j];                s[start + end - j] = temp;            }            start = i + 1;        }    }    return s;}

Python版

还是Python方便，这里需要注意字符串翻转操作s[: : -1]，表示s[begin : end : step]，由于起点和终点是整个字符串，步长为-1就实现了反向操作。

class Solution(object):    def reverseWords(self, s):        """        :type s: str        :rtype: str        """        return ' '.join(s.split()[::-1])[::-1]