Microsoft Loves This Coding Question! | Reverse Words in a String - Leetcode 151

FAANG Coding Interviews / Data Structures and Algorithms / Leetcode

[GregHogg]

Sorry, it should be "the sky is blue" -> "blue is sky the"!

[AngryEgg]

Bro is taking 3 left turns instead of 1 right

[danielhaveman]

That code is waaaay too complicated. You only need to do 4 steps:
- split on spaces
- reverse the array
- filter the array for any empty strings (the null between the two spaces, at the beginning and at the end)
- join the array with a space again

so: " hi there ".split(" ");

no need to trim separately, or to track things manually in a loop

[AverageSensei]

Bro the type of guy to park the furthest from the grocery store

[sophiophile]

I think a more elegant (and memory efficient) solution is to iterate over the chars backward and while char != ' ', add the chars to a string rev_word. Each time the loop breaks, ans += ' ' + rev_word[::-1] and rev_word = '' (also, add on the termination of the for loop if rev_word isn't empty). Same time complexity, but lower memory complexity. Plus no extra logic necessary to handle weird extra whitespaces.

Memory complexity for your solution is O(k) where k is the number of words, this is O(1).

[merveillevaneck]

Dude. Strip + reverse loop + character buffer using a stack + store resulting words in the buffer in an array every time you find a whitespace. Then join the array at the end. 2n runtime

[salism]

Thanks. This is an accepted answer in Python:
' '.join(s.split()[::-1])

[antonivanov]

You can do it with no additional memory by just reversing the whole string first and then reversing each word(using two pointers technic)

[thescientist]

normal people: Just use split() or the equivalent in your language... solved in one minute.
me with arm assembly without any libraries : "this little maneuver is gonna cost us 51 years!!"






ya ik using asm is stoopid for coding interviews.

[jjpaq]

Regex replace all `\s.*?` matches with ` ` and then trim() would work for the spacing issues, no?

[TonyFarley-gicv]

Honey even the conversation to the wording is mathematically aligned together

If you use .split() or .split(None) instead of .split(' ') then you don't need for-loop nor .strip(' ')

def rev(txt): return ' '.join(txt.split()[::-1])

And if you really need to use space (or other char) in .split(' ') then you may use filter(None, list) to remove empty strings from list

def rev(txt): return ' '.join(filter(None, txt.split(' ')[::-1]))

[corbinfonville]

I think the for loop is overkill. Just: str.split(' ').filter(s => !!s).reverse().join(' ')

[Eknoma]

You don't need a custom for loop to do a super common operation...
"...".split() does exactly what you would expect, removing all whitespace, so e.g.
" this is a \t string ".split()
Gives you
["this", "is", "a", "string"]

So the way to do this task in Python is just
" ".join(reversed(inp.split()))

[briandavis]

Can you use split and join? Then maybe a trim instead of all that parsing

[Phrozends]

Without using so much memory for large inputs, we could use a the regular stack tecnique that gets flushed on spaces. You do it in O(n) time too.

[FakeDumbDummy]

the sky is blue
blue is the sky

bro failed test cases in dry run

[prasadsawant]

Even though if we don't provide the separator to split, still it splits the string as expected without including those spaces in the list.
I did it in one line:
return "

[pound]

can you use the split function ? btw I love your content!

[chandings]

sir what about, or . or any other punctuation. ususally there is no space between words n punctuation