leetcode_gym/_problems/reverseWordsInAString3.md

layout, title, last_solved, category, leetcode_url, status

layout	title	last_solved	category	leetcode_url	status
page	Reverse Words in a String III		string	https://leetcode.com/problems/reverse-words-in-a-string-iii/	Solved

Problem

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.

Solution

Some things to note:

• can't do swaps on string characters, need to convert to list first
• string.extend() takes content of list and appends it to another list

{% highlight python %}

def reverseWords(self, s: str) -> str:
    
    letters = list(s)   
    
    def reverse(letters, startIndex, endIndex):
        
        left, right = 0, endIndex
        
        while left<right:
            
            # can't do item assignments on strings, therefore need to turn to list first (like toCharArray() in java)
            letters[left], letters[right] = letters[right], letters[left]   
        
            left+=1
            right-=1
        
        return letters
    
    
    tokens = s.split(" ")
    
    output = []
    for token in tokens:
        
        reversed = reverse(list(token), 0, len(token)-1)
        output.extend(reversed)     # extend extracts contents from list and appends to other list
        output.extend([" "])
    
    output = output[:-1]        # remove last space value
    
    print(output)
    
    return "".join( output )

{% endhighlight %}

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{% highlight python %}

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