Reverse String - 3 Ways - Leetcode 344 - Python

0:00 - Read the problem
1:02 - Iterative Solution
4:16 - Stack Solution
6:18 - Recursive Solution

leetcode 344

#microsoft #interview #python
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[rideraff]

Hey @NeetCode thanks A TON!! I couldn't have cracked FAANG interviews without your help. I interviewed with 3 FAANG companies and got offer letters from 2. This is the biggest milestone of my life and yes a dream come true. So thank you very much for all the great work you're doing :) You THE G.O.A.T.

[uditsharma]

Direct swap and stack solutions were intuitive for me but didn't notice that we could also use recursion. Thankyou for showing multiple solution instead of giving just the most efficient one. 👍

[gianniprocida]

This channel is extremely undervalued. It should have at least 500K subscribers.

[NeetCode]

A big change from yesterdays Hard to todays... reverse a string

[shakhaoathossain]

Slicing works but Incase interviewer doesn't allow us to use built in functions then swapping is great

[Cloud-]

Please I need an advice. I have been doing leetcode questions for over 3 months now (this is my first time. I’m new to this). I have definitely improved but I don’t think I’m ready for technical interviews yet. How do I improve quickly? I really need to find a job asp for my own mental health wellbeing

I think the biggest reason the input is a "char[]" instead of "string" because in most languages strings are immutable. That means, you can't change them once you create it. Even if you think you change them, you actually create a new string object which automatically means that you need an extra memory.

[__________________________]

No way, I love you because you upload videos everyday.

[harveylesterarcilla]

using slice trick print(s[::-1]) should work as well

[NotKevinNguyen]

Isn't s.reverse() also works for this problem?

[fieryfeather]

Would the space compexity of the recursive solution be O(1) for languages that support tail recursion?

[christinaphan]

thanks for the videos!

also, what software are you using to draw?

[floydian]

Incase someone is looking for a solution for a string:
def reverse(s):
if len(s) == 0:
return s
return (reverse(s[1:]) + s[0])

Here is how it works:
Input: "hello"
reverse("hello")
reverse("ello") + "h"
reverse("llo") + "e"
reverse("lo") + "l"
reverse("o") + "l"
reverse("") + "o"
=> "" + "o"
=> "o" + "l"
=> "ol" + "l"
=> "oll" + "e"
=> "olle" + "h"
=> "olleh"

[algorithmo]

What software do you use to record your videos?

[lymphtics]

Could someone explain what would be the space and time complexity of reversing a string in JS using built in methods like

[kritikabhateja]

Why s=s[::-1] is not working? Could you please tell.

[domeshsinha]

if possible to use nodeJs then please solve problem on nodeJs

[dandendrasingh]

Aren't the first solution is n/2? And why the stack solution is faster then the first one.

[numberonep]

Two other solutions,

first another even less efficient stack solution:
class Solution:
def reverseString(self, s: List[str]) -> None:
"""
Do not return anything, modify s in-place instead.
"""
stack1, stack2 = [], []
while s:
stack1.append(s.pop())
while stack1:
stack2.append(stack1.pop())
while stack2:
s.append(stack2.pop())
then another iterative solution :
class Solution:
def reverseString(self, s: List[str]) -> None:
"""
Do not return anything, modify s in-place instead.
"""
n = len(s)
for i in range(n//2):
s[i], s[n-i-1] = s[n-i-1], s[i]

Making it 5 more or less efficient ways to do the same thing xD coding is fun

[_sam_ael]

I used a while loop, then i start print with the last index the ... Until the index 0