Unique Paths | Dynamic programming | Leetcode #62

[@saurabhsomani9188]

Somebody give this man a medal ASAP. Crystal clear explanations on each and every problem. Very Inspiring and Helpful.

[@techdose4u]

🤣 Hahahahaa.....Thanks for appreciating :D

[@dumbcurious450]

Everyone starts with matrix directly no one says why this would work. this Man is someone who tells the exact logic behind it. Great work Mate ...

[@techdose4u]

Thanks :)

[@rahulbawa3969]

Its been 10 months and this Guy still hasn't received a medal!!!! You deserve it man! Thanks for explaining this nicely.

[@techdose4u]

Welcome :)

[@savvy9431]

This is how a coding problem should be explained.............. Everybody needs to learn from this man right here.!!!!!! Hats off🎉🎉

[@VrickzGamer]

I like Your Dark theme in the videos which gives my eyes the power to view more.

[@venkateshmusuvathi8468]

Salute to ANYONE who gets this interview question and solves it within half n hr

[@imshivendra]

I think TechDose Sir has joined Google. Congratulations.

[@thiyagarajanr225]

This man is so good at segementing the problems ! More power to you bro! A Die hard fan of you bro 💗

[@techdose4u]

Thanks :)

[@imshivendra]

I think TechDose Sir has joined Google. Congratulations.

[@ashishupadhyay6881]

Start watching at 10:40. Great stuff btw, thanks for this.

[@HemanthaKumarYadav]

Most underrated channel ! Hatsoff to you brother !

[@techdose4u]

Thanks :)

[@rutachaudhari5774]

You are way underrated for your work. Thanks for the solutions!

[@techdose4u]

Welcome :)

[@lavanya_m01]

This universe needs people like him!! Protect him :)

[@sudhanshukumar1558]

I have already solved this problem 2 months back, hence I copied my code from there. It was bottom up approach. Good to know about the top down approach.

[@techdose4u]

I had shown bottom up in dungeon game and so I took top down this time XD

[@CostaKazistov]

Top-down DP runs slightly faster (for some reason)

[@maansi3968]

The Explanation is soo great....just came through an one line python solution. return math.factorial(A+B-2)//(math.factorial(A-1)*math.factorial(B-1))

[@techdose4u]

Thanks

[@aminumado6973]

Best explanation for the unique paths problem.

[@md_aaqil8027]

Mind-blowing Explanation I am a fan of the way you think and solve the problem bro

[@imshivendra]

I think TechDose Sir has joined Google. Congratulations.

[@Ayush-xx1bx]

Can't thank you enough, I was stuck for hours with this approach. Now I understand it completely.

[@imshivendra]

I think TechDose Sir has joined Google. Congratulations.

[@adityagoswami6881]

The best explanation,you deserve 1 Million subscriber .

[@techdose4u]

Thanks ❤️

[@imshivendra]

I think TechDose Sir has joined Google. Congratulations.

[@RohitSubedi]

You can minimise the space complexity to O(M). Following is the Golang code: func uniquePaths(m int, n int) int { grid := make([]int, m) for i := 0; i < n; i++ { for j := 0; j < m; j++ { if i == 0 || j == 0 { grid[j] = 1 } else { grid[j] = grid[j] + grid[j-1] } } } return grid[m-1] }

[@techdose4u]

We can optimize the space even in CPP by just maintaining a single array because we are just looking at 2 previous values :) top and left.

[@rubinluitel158]

how is this better? if you have have an array size 5, it executes 5^2 times for the videos solution but your solution also executes 25 times.

[@vaishnavinatarajan3987]

Simple solution and awesome explanation ! Too helpful.

[@oqant0424]

Ur channel is a goldmine

[@imshivendra]

I think TechDose Sir has joined Google. Congratulations.

[@shubhammishra1225]

bohat shi samjhaya ...

[@hariprakash4237]

Sucessfully completed. Thanks for this workout

[@techdose4u]

Welcome :)

[@rogerknight8447]

By combinatorics its like (m+n-2)C(n-1). An better SC approach though!!

[@tecocode6070]

Roger Knight how you explain this approach?

[@sulekhakumari-hs4gy]

@@tecocode6070 this problem is eqivalent to permute (m-1) down move and (n-1)right move.

[@saitejdandge2315]

Let's say, we have r X c matrix. Let's take a simple way, all down, then all right, steps=r-1(down) + c-1 (right). Ironically every other way also takes r-1+c-1 steps. total ways is nothing but all permutations of given way (r+c-2) => (r-1+c-1)! / (r-1)! * (c-1)! => can be re written as (m+n-2)C(n-1)

[@siddusidh9705]

very good explanation , thanks a lot you are genius

[@DK-ox7ze]

Best explanation of this problem anywhere!

[@techdose4u]

Thanks :)

[@imshivendra]

I think TechDose Sir has joined Google. Congratulations.

[@DK-ox7ze]

@@imshivendra What's his real name?

[@imshivendra]

@@DK-ox7ze I don't know but I has seen on LinkedIn that he has joined Google

[@dhanashreegodase4445]

very helpful to me! thanks alot..You deserve many more likes

[@techdose4u]

Thanks

[@agileprogramming7463]

One of the easiest DP problems 😅 Also the Robot in thumbnail is 😍

[@kunalsoni7681]

Really you make this problem very easy to understand 😊😇.. thanking you sir 😊

[@techdose4u]

Welcome :)

[@ajaywadhwa3398]

What a superb explanations !! Really helped a lot.

[@techdose4u]

Thanks

[@NikhilKumar-of5gb]

Code with time complexity O(1) Code is like, nCr:-> Where, n=rows + columns -2 r = columns -2

[@Rahul-rp5hk]

How will you calculate ncr in O(1)? I guess it ll be O(r)

[@MrMarchador]

Very precise, clear, crisp explanation.

[@sathyamoorthy2888]

Iam grateful to your service sir

[@TONETHAJI]

Great explaination

[@ashutoshsinghrajawat6440]

Simply amazing ❤

[@yatri6329]

This video is a great explanation thanks for uploading this free....

[@techdose4u]

Welcome 😊

[@shobhitbajaj9667]

Thank you so so much You have such a great talent ❤️ of explaining complex things like piece of cake.

[@techdose4u]

Welcome :)

[@nandk45523]

Great explanation bro appreciate it

[@Tarunkumar-si4im]

Thanks a lot sir for crystal clean explanation❣️

[@techdose4u]

Welcome :)

[@imshivendra]

I think TechDose Sir has joined Google. Congratulations.

[@ALEEMKHAWAR1]

amazing solution sir

[@ShubhamMahawar_Dancer_Actor]

Its a cool solution but i have done it without recursion or Dp.I have done it by using binomial coefficient in which s.c=O(1)

[@techdose4u]

Share your code bro :)

[@manishmundra8902]

You deserve more likes sir..

[@techdose4u]

Thanks :)

[@bendesmedt9036]

Nice, you could also solve it using combinatorics: [ (rows - 1) + (columns - 1) ] ! / [ (rows - 1) ! * (columns - 1) ! ]

[@imshivendra]

I think TechDose Sir has joined Google. Congratulations.

[@CostaKazistov]

@@imshivendra I wouldn't be surprised. He is truly one of the best CS teachers here on KZbin. The guy who runs a similar channel (NeetCode) has also started working for Google last year.

[@noobCoder26]

thanks sir for this explaination

[@techdose4u]

Welcome :)

[@PriyankaSingh-pn8xv]

Amazing explanation, thanks

[@275phuongvy]

great explanation. Thank you

[@techdose4u]

Welcome

[@SuganthanMadhav]

Excellent explanation

[@techdose4u]

Thanks :)

[@acxd]

What are the Plans for July , another Challenge or Topic-wise !

[@techdose4u]

Topicwise graph algorithm.

[@nileshsinha7869]

GREAT EXPLANATION SIR ❤👌

[@techdose4u]

Thanks

[@imshivendra]

I think TechDose Sir has joined Google. Congratulations.

[@Moch117]

Nice video. Most videos start from f(m-1,n-1) i.e the bottom right but I solved it starting f(0,0) just like you I ask myself at each step : what can i do. I can either go down or go right. Then i ask what does my f(i,j) represent. In this case, it means the number of ways I can get to the bottom right starting at i and j. This means to calculate f(i,j), i need to know the number of ways I can get to bottom right if moved right + number of ways if I move down

[@thegreekgoat98]

The Best!

[@ismail8973]

I literally loved this problem. Any way best explanation as always

[@imshivendra]

I think TechDose Sir has joined Google. Congratulations.

[@shresthmishra9329]

Nice drawing 👌 😅

[@spetsnaz_2]

Robot is better than anything 😂🤖

[@techdose4u]

Atleast someone understands art 😭

[@saitejdandge2315]

Let's say, we have r X c matrix. Let's take a simple way, all down, then all right, steps=r-1(down) + c-1 (right). Ironically every other way also takes r-1+c-1 steps. total ways is nothing but all permutations of given way (r+c-2) => (r-1+c-1)! / (r-1)! * (c-1)! => can be re written as (m+n-2)C(n-1)

[@dontgiveup5271]

Great explanation !!!! A small doubt at 13:32 I know from line 23 its used for fastIO but can I get some explanation on it. Thank You.

[@imshivendra]

The height of a conical tank is 12cm and the diameter of its base is 32cm. The cost of painting if from outside at the rate of Rs 21 per sq. cm. is

[@brandoncontreras343]

THANK YOU!!!!!!

[@techdose4u]

Thanks

[@Tarunkumar-si4im]

👍👍

[@techdose4u]

👍🏼

[@prasantharavindramesh1078]

@techdose Awesome explanation Let's assume that the robot can move in all directions Then how can I modify the solution?

[@techdose4u]

Assume it like a graph with 4 adjacent edges and then solve :)

[@vibekdutta6539]

Awesome, Sir what will be the complexity of we use combinatorics for the solution, I think there is a direct solution using combinatorics

[@amanbarnwal6668]

Awesome content as always :) Just a simple query, at 4:07 I believe the recursive tree for node (1,0) in the right subtree is drawn wrong. Please correct me if I'm wrong.

[@imshivendra]

I think TechDose Sir has joined Google. Congratulations.

[@kamele0278]

what is the point of dynamic programming if you are not using recursion ?

[@gaunikasrivastava7851]

What is time complexity of the recursive approach?

[@bisatisrilatha7957]

what is time complexity in recursive approach and DP ?????? why?????????

[@saurabhkanswal7954]

Not all heroes wear caps:)

[@techdose4u]

:)

[@E__ShameemahamedS-bx2ed]

It's very similar to minimum cost path

[@techdose4u]

Yea :)

[@E__ShameemahamedS-bx2ed]

@@techdose4u Pls explain what is bottom up approach and top down approach

[@shyamprakashm6325]

Could we possible to print all the unique paths? If yes how it is?

[@shivasaini4097]

❤

[@techdose4u]

😊

[@muhammedjack8303]

great

[@techdose4u]

Thanks

[@ASocial093]

Did you get leetcode s t-shirt previous month? I think you got it. 😁😁

[@DreaMagnifier]

it's standard combinatorics problem

[@techdose4u]

👍

[@vijayj1997]

Can anyone explain , after breaking the dptable both robot and star are at same cell(0,0) then how the number of path will be 1?

[@VrickzGamer]

how many are not from IIT/NIT/BITS ?

[@E__ShameemahamedS-bx2ed]

Me

[@VrickzGamer]

Are you from NIT?

[@shailygoyal5174]

time n space complexity?

[@HARINIKUMAR-qm3jc]

I tried doing Binary Tree in timestamp 4:17 myself and found that child from node (1,0) to be (1,1) & (2,0) but in the video it is given as (1,2) could you explain me how? Thanks in advance

[@AlokDhanush-um5ol]

Tha was a mistake in the video.. It must be (2, 0) instead of (1, 2)..

[@HARINIKUMAR-qm3jc]

@@AlokDhanush-um5ol Thanks for taking time and replying :)

[@backtobasics6865]

code link doesn.t opens

[@snehan3341]

sir i cant understand how he says x and y are 3..? 2:50

[@jeantharappel6633]

Why not just calculate (m+n-2)! / ( (m-1)! * (n-1)! )

[@Moch117]

Not everyone knows this formula lol

[@jeantharappel6633]

@@Moch117 it isn't a formula i used logic to covert the problem, consider m columns and n rows to get from one corner to another you need to move right (m-1) times and move down (n-1) times. The problem then becomes a permutations problem of which there are many variations. Say n is 3 and m is 4 and a down move is represented by d and a right move is represented by r. The number of permutations of rrrdd say rdrdr, rddrr etc is 5!/(3!*2!).

[@krishnakantsharma6161]

hve anyone noticed pattern in dp table 👀

[@md_aaqil8027]

Java Solution class Solution { public int uniquePaths(int m, int n) { int mat[][]=new int[n][m]; for(int i=0;i

[@_Rich_YT_]

who is feeling frustrated now ??