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

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

class Solution 
{
    public String reverseWords(String s) 
    {
        char [] arr = s.toCharArray();
        int p1 = 0;
        int p2 = 0;
        
        while(p1 < arr.length)
        {
            // let p2 find the space
            while(p2 < arr.length && arr[p2] != ' ')
                p2++;
            
            // once p2 find the space, do reverse between p1 and p2
            int left = p1;
            int right = p2 - 1;
            
            while(left < right)
            {
                char temp = arr[left];
                arr[left] = arr[right];
                arr[right] = temp;
                
                left++;
                right--;
            }
            
            // reset p1 p2
            p1 = p2 + 1;
            p2++;
            
        }
        
        return new String(arr);
    }
    

}

参考资料：n/a

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