Increasing Triplet Subsequence - LeetCode 334 - Python [O(n) time and O(1) space]

Explaining how to solve Increasing Triplet Subsequence in Python

@1:23 Example walkthrough
@6:14 Code
@8:27 Code run-through + final example
Music: Bensound
Lemme know if you have any comments or questions!:)))

[NayemUddinBiswas-ym]

The dry run at the end of the tutorial made the whole thing more comprehensible to me. Thanks for such an explanation.

[neilijason]

Compared to other tutorials, you explained it in a way that is easy to understand. Giving more examples and going through the whole algorithm really helps. Thanks, I love it!

[chittillavenkataviswanath]

One of the finest explanations you'll find on the internet.

[ZanarkandStarplayer]

You're the first person to make this easy to understand! Thank you!

[amartyaganguly]

It took some time for me to understand why this logic works. Correct me if I am wrong:
At any step the current value at nums_i or nums_j does not matter as long as they have some value that is not +infinity.
What this means is, if we have reached the line: else return true it means there is already a value set at nums_j and that also means somewhere in the iteration we have set a value at nums_i which is less than the current nums_j [ ** irrespective of the current nums_i ** ].

[sai-codes]

Such a simple solution. Can't believe I didn't think of this.

[lakshmiivaturi-ot]

Best and simplest solution with a neat explanation. Thanks Deepti

[bryankhor]

Her solution was so easy it made realize that I overthink too much lmao

[ers]

Thank you for saving me hours of headache!

[thanhn]

Great video. This makes sense after watching this video about 3 times. Sad, I don't think I would have come up with this solution.

[angushardy-francis]

You explained this very well - much appreciated :-)

[PeakyBlinder-lzgh]

this is the only video i can coprehend for lc. 334. thx

[ICloudyFi]

i = 0

while i < len(nums):
if nums[i] < nums[i+1] and nums[i+1] < nums[i+2] or nums[i] < len(nums) - 1:
return (True)
else:
return (False)
i += 1

[makealemonade]

Thanks for this video. I don't know why I was stuck at j < i case.

[manishamuskan]

the solution doesn't satisfy for this array - [20, 100, 10, 12, 5, 13]. If you dry run it to verify, it doesn't satisfy the condition i<j<k. At 5th iteration - num_i = 10, num_j=12 and num=5, when runs inside loop, it passes through first if condition and num_i becomes 5. At 6th iteration, num = 13 and it doesn't pass through any of the if condition hence returning true. But at this point, num_i = 5, num_j = 12, num=13 and indices are i=4, j=3, and k=5 which doesn't satisfy the condition i<j<k. Hence this solution is not correct.

[ankitpandey]

Thanks a lot Deepti. Explanation was great !

[nick]

Congrats on getting a complete submission. However, I think this LeetCode Problem is broken.

What happens if your solution was applied to this? nums = [20, 100, 10, 12, 5, 13]

What happens if num_i is updated but now it's index value is greater than num_j's? This would break the i < j < k condition, however, you don't see that in some solutions I've seen that were submitted.

[johnming]

Hey Deepti... your videos are really amazing... can you please do a video on this problem..

Input: [”long”, “very”, ”jump”, ”verylongjump”, “longjump”, ”iconstar”, ”star”, ”icon”, ”icons”, ”tar”, ”stars, ”iconstars”]

output:
“verylongjump”: [“very”, ”long”, ”jump”]
“verylongjump”: [“very”, ”longjump”]
“iconstar”: [“icon”, ””star”]
“iconstar”:[“icons”, ”tar”]
“iconstars”:[“icon”, ”stars”]

[ahmdrn]

Consider the following array to be our input: [20, 100, 10, 12, 5, 13]
i will be 5
j will be 12
and k will be 13
and it will return True. however this is not a correct subsequence because j come before i not the opposite
I can't understand why is this a correct solution (I understand we don't return the indexes so our solution is correct because it returns true because 10 can be i 12 can be j 13 can be k)

I found this solution is widely used and i would appropriate it if someone explain to me why is it correct

[PersonalUser-yrvb]

Its works for this problem but what if similar kind of problems like return first three numbers of those pair.For example[2, 1, 3, 0, 4, 6] in this i want to return those first pair as 1, 4, 6 how can we solve these type of questions