557 Reverse Words in a String III 反转字符串中的单词 III
Description:
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:
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.
题目描述:
给定一个字符串，你需要反转字符串中每个单词的字符顺序，同时仍保留空格和单词的初始顺序。
示例 :
示例 1:
输入: "Let's take LeetCode contest"
输出: "s'teL ekat edoCteeL tsetnoc"
注意：在字符串中，每个单词由单个空格分隔，并且字符串中不会有任何额外的空格。
思路:
按空格分割开字符串, 依次反转
时间复杂度O(n), 空间复杂度O(n)
代码:
C++:
class Solution
{
public:
string reverseWords(string s)
{
int j = s.find(" ") == s.npos ? s.size() : s.find(" "), i = 0;
while (j <= s.size())
{
if (s[j] == ' ' or j == s.size())
{
reverse(s, i, j - 1);
i = j + 1;
}
++j;
}
return s;
}
private:
void reverse(string &s, int i, int j)
{
while (i < j)
{
s[i] ^= s[j];
s[j] ^= s[i];
s[i++] ^= s[j--];
}
}
};
Java:
class Solution {
public String reverseWords(String s) {
String[] temp = s.split(" ");
for (int i = 0; i < temp.length; i++) temp[i] = new StringBuilder(temp[i]).reverse().toString();
return String.join(" ", temp);
}
}
Python:
class Solution:
def reverseWords(self, s: str) -> str:
return ' '.join([word[::-1] for word in s.split(' ')])
