First Missing Positive || Intuition + Example + Explanation || Must Do for Amazon

Given an unsorted integer array nums, return the smallest missing positive integer.
You must implement an algorithm that runs in O(n) time and uses constant extra space.
Example 1:
Input: nums = [1,2,0]
Output: 3
Example 2:
Input: nums = [3,4,-1,1]
Output: 2
Example 3:
Input: nums = [7,8,9,11,12]
Output: 1

[@divyadwivedi1527]

The BEST Explanation on UTube , got a new approach to learn,Thanks a lot

[@bhandarkarsomesh8277]

such a great explanation, never going to forget the chair example !!

[@learnwithayush7838]

I must say this is very underrated coding channel . You must Do an Q/A 😀

[@piyushsingh9320]

Not all superheriones wear capes, some of them make videos to help others..

[@probabilitycodingisfunis1]

Thank you so much Piyush!!

[@andiamakaza24]

yeh aach tha

[@adityarangra9019]

aap sach mein kaafi acha explain krte ho meine 4-5 videos dekhi so that ki koi small length ki video mein explain krde.... but at the end merko yahi par aa kr ke samjh aaya pura concept ....................... your explaination is so easy to understand..... hard question bhi easily samjh aa gya

[@jethala138]

Sweety ran away with Guddu Bhayia, that's why she was not able to sit on her chair :) Btw great explanation thanks.

[@probabilitycodingisfunis1]

Haha lol :)

[@AmanTheMystery]

thanks mam great explanation, keep doing good work it helps all

[@Itachi16-U]

I went through 2 to 3 videos in youtube. No one explained better than you. Thanks for the better explanation.

[@himanshulal8345]

Nice explanation for a tricky problem... thank you..

[@dhruvsanghvi5562]

Your explaination is really great and creative, liked a lot

[@gkushwanth2277]

superb explanation. I saw many videos for the approach of this question,among all your explanation I easily understood.

[@pranjalmodanwal7842]

best expanation on youtube. Thanks a lot!!!

[@davidmwangi4312]

Great Explanation,

[@trinitykhuman]

Great explanation. Thanks

[@karandeepsingh6201]

Wonderful explanation

[@kameshwarmehta8435]

u have explain different approach for these question,thanku mam🙌.but u have missed one edge condition for swapping,that ele >0 && ele

[@mohit7717]

I like the Mother and childs example.... Nice explanation

[@harshavardhanpatekar5697]

Great explaination!!

[@akhilkhandelwal3927]

Great Explanation di 😄. Completely Understood.

[@shadabahmadkhan4986]

Thank you ! very well explained

[@deep14054]

Hi ma'am thanks for the solution, I came up with this solution: int firstMissingPositive(vector& nums) { int ans = 1; sort(nums.begin(), nums.end()); for(auto i: nums) if(i == ans) ans++; return ans; }

[@isdardedilkisifarish3366]

nlogn hai ye solution

[@sajalsrivastava4655]

luv u ......ek no explanation

[@cringeworld8708]

Osm solution🤜

[@sahirmuzaffar883]

best explanation

[@BACSShaileshShettar]

great explanation!

[@JehadiHellTransportAgency]

great work sis

[@vakhariyajay315]

Thank you very much.

[@karthikp6473]

By far the easiest approach ever

[@nikhilsatyam4815]

again you explained it very well. di i have a question, i solved the question but i forget the solution after some days waht to do in this conditions.

[@ASR-mz3cc]

mam plz can u make videos on trees data structure, after three months we have placement interviews in college .in fact good explanation with understanding examples :)

[@spritual_things05]

Thank you so much sister

[@AyushSingh-nu3gt]

too good !

[@venkateswaraswamyallumolu191]

What is the difference between keeping the line “int chair = element -1 “ inside the condition and outside the condition

[@Idukhan-jj9kc]

Perfect

[@vyankateshzawar7999]

best ❤

[@ugempireninjaaaaaahatori6755]

amazing solution , you just made mom play...

[@sahilverma03]

i think in the same way we do sorting in constant space, if numbers are positive

[@anvy_9924]

Hi, you explained pretty well, but the code is failing for this unit case. Input nums = [3, 4, 1, 1]. output = 1 expected = 2

[@abhaydeepsharma5027]

If anyone suffers that it is showing error , try to add condition for out of bound indexes for(int i=0;i0 && arr[i]0 && arr[i]

[@ipranavprashant]

Ahh gotcha, the similar approach you used to count the minimum no of swaps to sort the array..thnx

[@lavanyakataria101]

Grt example di, never going to forget

[@lavanyakataria101]

& Dii you are beautiful ☺

[@musharrafhussain130]

@@lavanyakataria101 us

[@sukiratsingh985]

How can you say that missing no is in range [ 1,n] because in this case [7,8,9,10,11,12] all the elements are >n=6

[@Rajesh-sr9us]

After seeing this i think you are underrated

[@AmanTheMystery]

no she is not under rated

[@lakshay6043]

i did this question before but forgot the logic. hope the story helps.

[@341yes]

Thanku!❤

[@muditkhanna8164]

technically the TC will be > than 0(n), athough great solution.

[@shvmsh20]

This story is the usp for the solution

[@princepal9886]

Thanks

[@sansai9329]

what if the first missing element range is from 0 - n? Taking chair = element instead of element -1 should work right?

[@tauffiqshaikh7419]

Yes, it does. Also, you must take care of element's range

[@CricketGalaxy07-18]

thanks

[@reshmamaam1451]

💯💯💯💯💯

[@ShubhamKumarSingh6224]

i thought girls are not good in coding but you proove me wrong and i'm happy to see my self being wrong

[@aizad786iqbal]

also , one suggestion, please add code links..

[@ashwinirathi238]

this approach is not optimal to handle this case [3,4,-1,1] to make this we need to tweak your code like this i think this sol is not optimal, i did some modification you can check n = len(nums) j=n while j: right_palace =True for i in range(n): element=nums[i] if element>=1 and element

[@lonen3rd]

Works, but is the time complexity still O(n)?

[@connecttorohit]

❤

[@aakashgupta7211]

Very secular mother😄 @5:00

[@probabilitycodingisfunis1]

Lol , had to mix up mine, brother's and few random names :)

[@AmanTheMystery]

Thanks alisha

[@sn8974]

Haaa bhosdiwala kitini bar message karega😂🤣

[@GauravKumar-py5br]

ma'am first test missing number should be 0 not 6

[@roshansadhasanker3525]

why did you asssing chair value after if ?? why not before ?

[@aviralarpan7350]

Lol

[@satyams8974]

Because if chair value >=nums.siz() , then in the if condition we will check for nums[char] which is invalid index. So with if condition we only give those values to chair which are lesser than size

[@GAURAV-ct9pl]

thank you

[@GAURAV-ct9pl]

mam, can you please tell me why can't we use swap(element,nums[chair]) instead of swap(nums[i],nums[chair])

[@sunnyseconds]

nums=[3,4,-1,1] def funcpos(nums): n = len(nums) i=0 for i in range(n): element=nums[i] if element>=1 and element

[@ashwinirathi238]

your code is not working because i=1-1 not impacted to original loop i variable i think this sol is not optimal, i did some modification you can check n = len(nums) j=n while j: right_palace =True for i in range(n): element=nums[i] if element>=1 and element

[@rabindrapatra7151]

Alisha has a brother named as Arman

[@aizad786iqbal]

I didn't understood the i-- part.. you were going to explain with an example then you stopped..

[@codingmaster7735]

i love you

[@abhijeetrishi6472]

i think this code will fail for array with repeating elements like [3,3,3,3]

[@kapilkumarsangwan6119]

no it will not , firstly have a look on the if condition of the code

[@ferozqureshi5228]

it’ll simply return 1.

[@rohit-ld6fc]

does not work for [3,4,-1,1]

[@likithareddy3025]

yes

[@ashwinirathi238]

@@likithareddy3025 @rohit yes this code not work for such case for that we have to made the change like and whihc makes it o(n^2) so not optimal n = len(nums) j=n while j: right_palace =True for i in range(n): element=nums[i] if element>=1 and element

[@gaurav4270]

It works make sure ur decrementing i after swapping

[@AmarjeetKumar-to9ub]

6:25

[@anurag_dutt]

We Don't care.

[@abhishekpati2006]

one of the most worst explanation 🤮

[@akshatkaushik2037]

Line 6: Char 29: runtime error: signed integer overflow: -2147483648 - 1 cannot be represented in type 'int' (solution.cpp) SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior prog_joined.cpp:15:29 help for this error

[@debayanbiswas3563]

Take chair and element as long

[@Vipulghadi]

[@shashwatchawla]

[@VivekKumar-lc3vg]

❤️