The Number of Beautiful Subsets leetcode || Dynamic Programming || Backtracking || Leetcode-2597

[@ARYANMITTAL]

Code & Notes: leetcode.com/problems/the-number-of-beautiful-subsets/solutions/3316187/image-explanation-both-o-nlogn-o-2-n-approaches-best-explanation-on-leetcode/

[@cenacr007]

keep up the good work

[@mayankgarg4232]

cool dude..really a good explanation for a beginner like me..thnx

[@K_SE_SaketVerma]

Wonderful explanation , keep up the good work !

[@nkvs1248]

Oooooo Required a lot of patience , Nice one......!!!

[@HandyEngineering]

nit: you do not need to sort vector v before you push items into the map mp2 (map is sorted anyway and this is why the code works)

[@kashishchawla2754]

Can you please please make a video f question number of 1994 the number of good subsets , I am not getting the overall concept and nobody solves such tough questions on youtube except you! It would be of great help to all of us!!! Thanks!

[@shabnamhaque3784]

if returning 1 in base case confuses you u may try thisclass Solution { public: int dfs(vector&a,int ind,int k,unordered_map&mp){ if(ind==a.size()) return 0;//empty subset int taken=0,nottaken=0; if(mp[a[ind]-k]==0 and mp[a[ind]+k]==0) { mp[a[ind]]++; taken=1+dfs(a,ind+1,k,mp); mp[a[ind]]--; //take } nottaken=dfs(a,ind+1,k,mp); return taken+nottaken; } int beautifulSubsets(vector& nums, int k) { //make all subsets and count the good ones - brute force // make only good subsets int n=nums.size(); unordered_mapmp; int ans=dfs(nums,0,k,mp); return ans; } };

[@VarunSharma-xd8xd]

watched 2 times but i dont know what u did in the dp approach

[@cenacr007]

I don't know why by map.find() wasn't working at all for me, whether I used set or map.

[@bhumikanayyar2300]

why not use set in backtracking approach as we just care if nums[i]-k /nums[i]+k exists or not?

[@kergeysarjakin5592]

bro 1 and 4 itself can;t be taken bcoz 4-1=3 at 7:30

[@ARYANMITTAL]

Yaa yaa yaa, true true bro

[@killadasatyaaditya5960]

Can you explain why prevNotTaken is inititalized with 1 and prevTaken with 0

[@ARYANMITTAL]

As initially we have empty subset

[@GauravDuseja-t6q]

I was not able to implement backtracking proble what to do bhaiya

[@ARYANMITTAL]

Have you watched backtracking crash course bro?? 🫂

[@Munchen888]

Look. You have two options: take or not take an element. If you not take you just go further -> func(idx + 1); else take you should make a check if such element in defaultdict (dict) or not . If not you place the element in defaultdict and go further. But when you return you should remove from dict. Set in initial state .

[@satvrii]

Striver 2.0

[@ArnabBhadra02]

your vives match with striver

[@RohitKumar-cv7qb]

way of teaching is good, but that extra effort we require to keep attention on English, that's really irritating

[@hasii36263]

man this is a very bad explanation.

[@prashantdubey9984]

Is it necessary to move your hands ?? It's really irritating

[@tonytonychopper2485]

"irritating" is a strong word. If you say "It would be less distracting if you reduce the hand movement", that might deliver what you wanted to say without hurting his feelings.

[@ABHISHEKYADAV-lu5iz]

worst explanation ever.