LeetCode 557. Reverse Words in a String III (反转字符串中的单词 III)

Posted 2020-11-10 几米空间

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.

 

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题目标签：String

　　题目给了我们一串string，让我们把每一个word 给reverse一下。

　　设p1 和 p2，每一次让p2 找到 “ ” space，然后 reverse p1 和 p2 之间的 word，然后更新p1 和 p2 的值。

　　具体请看code。

 

 

Java Solution:

Runtime beats  96.43% 

完成日期：05/31/2018

关键词：Two pointers

关键点：反转p1 和 p2 之间的 word

 1 class Solution 
 2 {
 3     public String reverseWords(String s) 
 4     {
 5         char [] arr = s.toCharArray();
 6         int p1 = 0;
 7         int p2 = 0;
 8         
 9         while(p1 < arr.length)
10         {
11             // let p2 find the space
12             while(p2 < arr.length && arr[p2] != \' \')
13                 p2++;
14             
15             // once p2 find the space, do reverse between p1 and p2
16             int left = p1;
17             int right = p2 - 1;
18             
19             while(left < right)
20             {
21                 char temp = arr[left];
22                 arr[left] = arr[right];
23                 arr[right] = temp;
24                 
25                 left++;
26                 right--;
27             }
28             
29             // reset p1 p2
30             p1 = p2 + 1;
31             p2++;
32             
33         }
34         
35         return new String(arr);
36     }
37     
38 
39 }

参考资料：n/a

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