DP 39. Buy and Sell Stocks With Cooldown | Recursion to Space Optimisation

[@rupamhari115]

After watching previous buy and sell stocks problems, I solved variant IV, with cooldown and with fee by my own, without watching the videos. 1-2 months back, I had no concept of Recursion and DP, and now, I am confident to solve any kind of recursion and DP. Thank you so much bhaiyaaa. Huge respect to you. 🙏🙏🙏🙏

[@kazuma0803]

Same

[@bite091_jamee7]

same

[@asdsd-wu4yw]

those who are seeing this kind of comments dont worry u can also solve these problems ,there is only one word of change in code as compared to previous code,these are very simple

[@satendra6200]

same here bro

[@happysatan5554]

Where are u working now bro

[@nupur3177]

Want to share the significant difference between this channel and other million channels who claim that they teach DSA, other channels explain the code or sometimes when channel is good ,intuition as well, but striver neve fails to teach the concept behind every f problem, he will explain one problem, and you can do others extremely fast(relatively) and on your own as well because he did not give you a stupid reading of code, but he explained you how to generate the f code. Only Aditya Verma bhaiya's channel along with this channel has even come close to this level of DSA teaching, this has surpassed the GOD level as well. Kudos to striver !!!!

[@anandkalpe2155]

Solved previous two and this problem by my own just by watching your first two videos on stocks. Completed from recursion upto space optimization...Feeling good. Thanks striver for making it very simple !

[@Tejas-Coder]

After watching buy and sell stocks problems, I solved this problem by my own without any hints or watching videos. Thank you so much Sir!

[@yeddulaharshitha4405]

Thats insane ! I started DP 3 days ago. On the 4th day I am on this lecture. After watching all the buy and sell stocks, I was able to get the crisp of this in just few seconds.Kudos to you!!

[@jayrathod7957]

ohh just how??? for me,it took 1 month to reach till here...

[@aditya14-02]

​@@jayrathod7957++

[@calvincruzada1016]

watched from 1-40 of your DP videos. I feel like I can solve any DP problem now, thanks man :)

[@parthsalat]

Then why are you commenting on video 39?

[@calvincruzada1016]

@@parthsalat rewatching? I don't have photographic memory unfortunately :(

[@parthsalat]

@@calvincruzada1016 In that case, I recommend you to use notion. It's the best note taking tool out there.

[@calvincruzada1016]

@@parthsalat Good advice, I love notion! Been using it for years, it's my brain dump so I don't have to keep much in my head 😂

[@MEGHAPRAJAPATI-r3m]

we can space optimize because we don't have to carry entire row for i+2, only have to carry dp[i+2][1]. so we can use a variable to store it and update it with next2 = next[1]. this is the space optimized solution: int maxProfit(vector& prices) { int n = prices.size(); vector next(2, 0), curr(2, 0); int next2 = 0; for(int i = n-1; i >= 0; i--) { curr[0] = max(next2 + prices[i], next[0]); curr[1] = max(next[0] - prices[i], next[1]); next2 = next[1]; next = curr; } return next[1]; }

[@piyushpandey244]

i also tried using one extra variable for the two ahead variable here is the code int Maxprofit(vector&prices){ int n = prices.size(); vectorahead(2,0); vectorcurr(2,0); int twoahead = 0; for(int ind =n-1;ind>=0;ind--){ for(int buy=0;buy

[@sricharanreddy9989]

After understanding the pattern i could solve these questions listening to music in like 5mins , your explanation is just amazing bro ❤‍🔥

[@viratlover6206]

I was able to solve this problem from recursion to the space optimization by own. Thank u so much sir!

[@SumitKeshariMCS]

Solved it using 3D DP concept taught by you. I didnt watch the video and tried to solve it by myself. class Solution { private: int solve(int index,int n,int buy,int cool,vector& prices,vector& dp) { if(index==n) return 0; if(dp[index][buy][cool]!=-1) return dp[index][buy][cool]; int profit; if(buy==0 && cool==0) { int op1 = solve(index+1,n,0,cool,prices,dp); int op2 = -prices[index]+solve(index+1,n,1,cool,prices,dp); profit = max(op1,op2); } else profit = solve(index+1,n,0,0,prices,dp); if(buy==1) { int op1 = solve(index+1,n,1,cool,prices,dp); int op2 = prices[index]+solve(index+1,n,0,1,prices,dp); profit = max(op1,op2); } return dp[index][buy][cool] = profit; } public: int maxProfit(vector& prices) { int n = prices.size(); vectordp(n+1,vector(2,vector(2,0))); for(int index=n-1;index>=0;index--) { for(int buy=0;buy

[@yugal8627]

Bhaiya watched all your DP videos till now and I'm able to solve the previous and this questions by myself. Thanks a lot..🙏🏻🙏🏻

[@mdamirhussain2095]

Understood... Thank u Striver

[@ntgrn-pr5yx]

Thank you striver , Understood

[@lexeve5298]

Thanks striver , I was able to come up with the logic myself

[@UECAshutoshKumar]

Thank You! Understood!!!!

[@princeshubham26]

solved by myself ,,,self confidence is building

[@ishangujarathi10]

Understood, got the logic by just reading the problem on leetcode and even did it myslef with both memoization and tabulation technique!!! Tysm Striverrrr!!!

[@preetkatiyar969]

Sir you are really a gem . These topic are really tough but you teach like this is just a mind game. Best teacher

[@aligohar1708]

the power of cp can be seen by his speed .... insanely impressed... I don't know, this guy does not even need interviews for companies, he should just be directly hired

[@divyansh2212]

I solved this question on my own without watching this video before. Thankyou Bhaiya

[@shubhamjaiswal1325]

Best Explanation so far. Very intuitive. Thanks a ton

[@rishabhgupta9846]

understood,able to solve by myself.Gaining confidence to solve dp questions

[@DevashishJose]

Understood Thank you so much.

[@Sid-ci1cd]

UNDERSTOOD!!

[@satyamgupta1446]

I was able to do this question on my own. Thanks striver for helping us out...😇

[@Superheroic_Anime]

Understood bhaiya !!! By just watching first 6 minutes of your video.

[@shubhankar_naik]

I was able to solve without seeing your solution thanks for the great explanations

[@johnsimon8158]

thanks for this awesome content

[@VinayKumar-xs6el]

Again i solved after pausing at 2:23 & i did on my own thanks from recursion to space optimization (java people has to use clone() for assigning arrays). not only this i did next lecture problem as well even without opening that from recursion to space optimization. thanks is small thing

[@ganeshkamath89]

Thanks Striver. Understood.

[@mohitsingh13]

Understood ❤

[@santoshb7776]

Understood sir 🙏🙏

[@vivekkumarsingh178]

Why we cannot optimise space when their was 2 for loops and just by removing one we are doing same thingh 😢???

[@atheisth2373]

Thanks a lot...Striveerr

[@rishabmalhotra6980]

I tried to space optimize it by mytself for 6 variables and I guess i fucked my brain so much that i started questioning my existence. You explained it so well thanks strive.

[@uditgarg6508]

put k = n/2 and ind+2 in previous , runs fine

[@divakarv3303]

Space Optimisation using 4 variables and 4 lines of code int a=0,b=0,c=0,z=0; for(int i=prices.length-1;i>=0;i--){ int x=z; a=Math.max( -prices[i] + b, a); b=Math.max( prices[i] + c , b); c=x; z=a; } return a; Thanks a lot striver for Graph,Tree and DP series

[@akashsahu2571]

yes

[@bibs24]

Thank you

[@LBK3]

understood ❤

[@Harsh-jc2bz]

diid it by myself

[@dum0]

damn i cant believe , i solved this problem under few seconds only listening question , actually getting gud

[@shivambajpeyi9008]

Understood, did this one by myself hehe

[@aditya14-02]

Thanks!

[@nihalsingh6233]

Understood

[@himanshuagrawal8012]

Thanku so much Raj bhaiya for DP videos , now i m feeling very much confident in DP, I can now teach to the interviewer as well 😜😜😅😅 just_kidding #UNDERSTOOOODDDDDDDD

[@Himani-t3g]

understood!

[@ratinderpalsingh5909]

Understood, sir. Thank you very much.

[@abdalla4425]

Understood!

[@asheshkaran5843]

UNDERSTOOD!!!!!

[@HarshKumar-ip5nr]

I have solved this question using 3d DP. Is this solution ok for the interview?

[@googleit2490]

DP revision: Was applying some other complex logic, had to watch the video upto 5:28 Nov'18 2023 02:51 pm

[@rishabhagarwal8049]

Understood Sir, Thank you very much

[@xpyder]

I think you can space optimize this easily by using Mod 3 on your array indexes (dp[ (ind+1)%3 ][0] and dp[ (ind+2)%3 ][1], etc), is this correct?

[@pusarlaaishwarya5035]

Canyou explain this condition please?

[@me.deepaksharma]

Thank You :)

[@keen_kartik]

This man is genius

[@kumarpurushottam632]

Thanks a Lot Striver : )

[@adityasaxena6971]

Thanks Striver

[@willastralian7141]

WHAT IS IT WITH THESE FUCKING EXCELLENT INDIAN TUTORS DUDE. CAN'T BECOME A SUPER POWER QUICK ENOUGH

[@Hello-ro6hr]

UNDERSTOOD ... Ideally at 15.09 it should be front1[1]...

[@VivekGawande1]

Great explanation!

[@hemantpatel1413]

understood.

[@parvahuja7618]

thankyou

[@kartikrameshchavan6662]

Understood 🙏

[@sauravchandra10]

Understood, thanks!

[@jivanninawe3190]

Striver bhahiya LIS pr dp banaho na bhaut question ke sath lis nahi samja muje

[@verma_jay]

understood

[@ajitzote6103]

understood!

[@rishabhraj8233]

solved without watching 😸👽

[@pankajmittal1002]

understood!!

[@mriduljain6809]

Understood Bhaiya..

[@parthsalat]

Understood kaka

[@tasneemayham974]

DONE!!

[@Professor-du2pf]

"US"

[@aditithakur6226]

Understood Sir.

[@VikashYadav-px8ei]

Understood 🎉

[@gangsta_coder_12]

Understood 💯💯💯

[@venkateshvenky2880]

#understood

[@vaishnavithakur6460]

Understood so very well!!!!

[@gaboja__goo]

thx very much.

[@parshchoradia9909]

Understood Sir!

[@sameersahu4569]

Understood!!!Thank you

[@nimmalavishnu3044]

Superb explaination striver

[@dheerajshukla7008]

thats amazing

[@gurubhargava6950]

Understood!!

[@gentleman7060]

In any videos of buy and sell stock u didnt mention overlapping. Why?

[@oblivion_5910]

understood

[@THEAMITESHRANJAN]

"us"

[@urvashi2410]

This was so good!!

[@shubhigupta5689]

Understood🌻

[@curiouscoder9566]

great content

[@satyampande684]

understood!!

[@Harshit126]

Understood, thanks

[@rohalkurup1350]

Understood !!!!

[@gopalaggarwal9649]

US

[@suheabkhan2546]

understood!!!!!!!!

[@calderanoadi5982]

UNDERSTOOD

[@vader9782]

well i did this i created an extra space for cooldown in the vector class Solution { public: int maxProfit(vector& prices) { int n=prices.size(); vector curr(3,0),next(3,0); next[0]=prices[n-1]; for(int i=n-2;i>=0;i--) { for(int buypt=2;buypt>=0;buypt--) { int profit=0; if(buypt==2) profit =next[1]; else if(buypt==1) { int buy=next[0]-prices[i]; int hold=next[1]; profit = max(buy,hold); } else { int sell=prices[i]+next[2]; int hold=next[0]; profit = max(sell,hold); } curr[buypt]=profit; } next=curr; } return next[1]; } };

[@priyanshvatsal9791]

Understood 😇😊