Lecture 49: Merge 2 Sorted Linked Lists || Sort 0s, 1s and 2s in Linked List

[@CodeHelp]

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[@myncom397]

the code is not correct for test case [5] , [1,2,3,4].

[@amitprakhar4802]

bhaiya ye TLE kyu de rha merge sort wala

[@avishkarpatil5871]

Approach 3 void sortArray(Node* head){ Node* temp = head; while(temp != NULL && temp->next != NULL){ Node* forward = head; while(forward != NULL && forward->next != NULL){ if(forward->data > forward->next->data){ swap(forward->data, forward->next->data); } forward = forward->next; } temp = temp->next; } }

[@nxtlvl2904]

Bubble sort se bhi kr skt hai n bhaiya

[@fgh427]

Babbar bhaiyya... I love you... Koii apna bhi itna help nhi karta jitna aap kar rhe ho.... Bhagwan aapko meri ummar bhi de de... Legend and GOAT....

[@yashsonune4391]

Glad I have completed 1/3 of the series, and still continuing.

[@parthdeshwal4419]

how long did it take you ?

[@iamvishnuranjan]

Bhaiya 1 month me (1- 49 )lecture 😍 what a course..

[@tjstar390]

BOTH Questions have unique concepts and bhaiya explain it very well,Thanks bhaiya.

[@Anmol-h8z]

at 41:15 while inserting a node between two nodes we can use : curr1->next=curr2; curr2=curr2->next; curr1=curr1->next; curr1->next=next2; and also why we are checking for next1->data >curr2->data > curr1->data we could just check with next1 only as we know we start with element with smallest value any value will be greater than or equal from starting node and then going further in list if curr2 is inserted and then new curr2 value will definitely greater than previous one

[@yashparalikar05]

Your teaching and your explanations are absolutely exceptional!!!

[@harshitkumar197]

I coded the 2nd one merge two sorted array by myself. i looked at ur approach discussion and did by myself. thanks for the giving me the confidence

[@therealartist9]

in which company you are working ??

[@priyanshpatel2078]

20:00 We can Simply Handle it by using this steps p3->next=NULL; p2->next=twoHead->next; p1->next=oneHead->next;

[@devanshusahoo]

Thank you so much for your lovely videos, you really make understanding the concepts a cakewalk! Glad to be your student.

[@divyareddy7622]

why cant zero and two 's list be empty here? he only took the case when 1's list is empty

[@Roshanhoro123]

thanks bhaiya for bringing all such good questions in this course and hats off to your efforts...aap itne busy hoke bhi regular videos daal rhe ho isse motivation milta hai ki chahe kitne bhi busy rhe humlog cllg exams me tb bhi hum pdhai krre... Thanks bhaiya...Keep smiling bhaiya bht suit krta hai aaapar..

[@tusharmukherjeeju-cse5773]

Can't believe that someone dislike this video ! 🙂 💔 If you buy a course which takes from you 20k that course never give you that kind of explanation . Love from Kolkata ❤️🙌

[@divyareddy7622]

why cant zero and two 's list be empty here? he only took the case when 1's list is empty

[@visheshkaran7083]

@@divyareddy7622 because even if two's or zero's list are empty they will be null and onetail->next will be null so it won't make any difference.

[@durgashreenv8426]

35:00 Explanation was just amazing, thank you so much!

[@RajveerKaur-ze1ll]

to check for the case when both elements have one one element, instead of adding a new if condition at beginning, we can also move the "if (next1==NULL)" condition outside the while loop, then also answer is correct, hope this helps.

[@prashantbpkumar510]

Exactly

[@tanishsinghal1879]

yeah boyh

[@unboxtheuniverse5336]

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Wow 😳😳😳😳😳 nya video aa gya..... Maza aa gya .... Abhi hi dekh lunga....🥰🥰🥰🥰🥰🥰🥰❤️❤️❤️❤️❤️❤️❤️❤️❤️🌷🌷🌷🌷🌷🌷🌷🌷🌷 Thanku bhaiya .... ❤️❤️❤️❤️

[@anmolkumar01]

at 55:44 , i think we don't need to add extra case when there is only one element in list one instead what we can do is - we can simply write that condition of if(next1== NULL and curr2 != NULL){ curr1 -> next = curr2; } it will take care of case at 55:44 as well as previous case when first list finish and second list still has some element and please feel free to to correct me if i am wrong ,

[@vmstudy9965]

Mjaa aa gya bhiya aaj to🎉 Finally I solved this problem myself. After watching this video

[@varaprasad8261]

Node* sortTwoLists(Node* first, Node* second) { if(first == NULL)return second; if(second == NULL)return first; Node* temp = first->data > second->data ? second : first; if(temp==first) temp->next = sortTwoLists(first->next,second); else temp->next = sortTwoLists(first,second->next); return temp; }

[@DipsOfficial802]

smaj gya bhaiya clear hai concept 🔥🔥🔥🔥

[@ujjwalverma_]

Bhaiya boht mja aa rha is course me. Paid me bhi aisa mja ni aata. Discord pe discussion and all. Great 🔥🔥🔥

[@chinmaykhemariya3816]

for 2nd question Node* sortTwoLists(Node* first, Node* second) { Node* a=first; Node* b=second; Node*k=new Node(-1);Node*tail=k; while(a!=NULL&&b!=NULL){ if(a->datadata){ tail->next=a;tail=a; a=a->next; } else{ tail->next=b; tail=b; b=b->next; } } if(a!=NULL){ tail->next=a; } else if(b!=NULL){ tail->next=b; }k=k->next; return k; }

[@kinmeensura4283]

very good explanation . now i am understanding everything . you are a very good teacher and motivator also, please keep it up 😅😅

[@115GAJBHIYESHREYA]

Thank you for providing an amazing series.

[@KaushikSharma-c3q]

Awesome explanation.

[@saswatighosh3162]

It was lit 🔥🔥🔥🔥🔥🔥🔥

[@avibirla9863]

Maza aa gaya bhaiya kya question tha merge wala 👍👍Or last ka edge case 👍♥️

[@laksheybanga8106]

Bhaiya I m your biggest fan! bas jldi se phase 2 khtm krdo bhaiya!

[@anuragpandey8165]

24:52 insertAtTail function kaha defined hai??

[@060_jiteshtripathi6]

bhaiya maza hi aagya, kya mast samjhate ho

[@anuragpatel7787]

hnji this is anurag patel Lec 49 completed successfully ✅

[@Josuke217]

My approach: SC: O(n) , TC: O(n) For 0,1,2. class Solution { public: ListNode* sortList(ListNode* head) { vector res; ListNode* temp = head; while(temp != nullptr) { res.push_back(temp->val); // Store value of current node temp = temp->next; // Move to next node } sort(res.begin(),res.end()); // Sort the vector // Now convert the vector into the sorted linked list int index=0; temp = head; while(temp != nullptr) { temp->val = res[index++]; temp = temp->next; } return head; } }

[@sounaksaha1455]

Present Bhaiya, consistency OP, videos OP, Reach OP.

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Hey! what does this OP mean?

[@prashantbirajdar9271]

ha bhaiyaa smja aya ache se ekdum bdiya❣😾❤

[@shubhammathur792]

amazing lecture bhaiya i think one of the best so far cleared every concept ;

[@verma_jay]

Bhaiya bhot acha pdhate ho aap

[@Hit-xe5uh]

Can't we simply apply selection sort in the first question?

[@priyanshujain862]

Amazing bhaiya 🤩🤩

[@saurabhrajput7492]

Watching CodeHelp + solving 450 DSA cracker sheet = cracking interviews

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[@shashnka]

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[@itz_arman_official__]

Thanks for your amazing content and your consistency is awesome bhaiya.

[@udaypratapsingh8923]

bhaiyaa ye hashing or heap bhi cover krva dena ... jab bhi ye sunta hui dar sa lagta hai 😅😅😅

[@mittalji919]

i used below merging algo and it is also working without any if condition nodeZTail->next = nodeO->next; delete(nodeO); nodeOTail->next = nodeT->next; delete(nodeT); head = nodeZ->next; delete(nodeZ); return head;

[@avishkarpatil5871]

Merge 2 Sorted Linked Lists - Approach 2 -> 99 % Faster void insertNode(Node* curr, Node* &tail){ tail->next = curr; tail = curr; } Node* mergeArray(Node* first, Node *second){ Node* addHead = new Node(-1); Node* addTail = addHead; Node* ptr1 = first; Node* ctr2 = second; while(ptr1 != NULL && ctr2 != NULL){ if(ptr1->data < ctr2->data){ insertNode(ptr1,addTail); ptr1 = ptr1->next; } else{ insertNode(ctr2,addTail); ctr2 = ctr2->next; } } while(ptr1 != NULL){ insertNode(ptr1,addTail); ptr1 = ptr1->next; } while(ctr2 != NULL){ insertNode(ctr2,addTail); ctr2 = ctr2->next; } Node* head = addHead->next; return addHead->next; }

[@hyphengamerandtech3064]

thank you bhaiya , placement ke baad aapko party meri taraf se .

[@RohitRana-tz2lr]

Thank you so much bhaiya for training our mind in solving a different variety of questions... hats off to you bhaiya...keep it up

[@RohitSingh-hc8yi]

2nd Problem was awesome!

[@anmolkumar01]

my approach for 1st question was that i just sorted it in two go without using extra space and in O(n) firstly : sort all the ones , if one present then remove it and link it to the head of list and update the head secondly : sort all the zeros , if 0 is present then remove it and link it to the head of list and update the head my code : void sort(Node* &head , int val){ Node* temp = head; while(temp->next != NULL){ if(temp->next->data == val){ Node* x = temp->next; temp->next = x->next; x->next = head ; head = x; } else{ temp = temp->next; } } } Node* sortList(Node *head){ if(head == NULL or head->next == NULL) return head; sort(head , 1); sort(head , 0); return head; } if there is any suggestion or correction then please feel free to correct me and above code is also accepted by the codestudio

[@Pawankumar-i8c]

thank you so much bhiaya for these precious lecture

[@lalitbisht8381]

merge wala question krke maza aa gya!!!!!!!!!!

[@kanikagupta2806]

concept++; understanding +++++++++; thankyou so much babbar bhaiya maza hi aagya..

[@divyareddy7622]

why cant zero and two 's list be empty here? he only took the case when 1's list is empty

[@kanikagupta2806]

@@divyareddy7622 beacuse 1's list is connecting 0's and 2's list. If 1's list is empty then approach discussed without if condition won't work. Hope it helps.

[@ayushp4471]

BEST explaination as always 🔥🙌

[@anuptewary3016]

Present bhaiya with lot's of Josh

[@saurabhmalviya100]

Kya baat hai mazaa aa gaya .josh is high and it should be High 😂😂😂

[@pahaljain9209]

Hat's Of bhaiya

[@ch0c0_1]

mza aagya bhai . Nice explanation

[@RohitSingh-hc8yi]

Thankyou for such a quality content

[@anuragpandey8165]

37:10 Just call sortTwoList(second, first) thats it.

[@justarandomguy6106]

How's that possible

[@samsmith3961]

concept finally samajh aa gya

[@aishavkhandelwal8271]

Mst ques tha dimag khul diya pura !! thx

[@tanbirsarkar2640]

sabse maza to linked list mai arha hai,,mast hai bahut,,basss pyar hojata hai

[@abhishekhsinha1551]

glad for your kind help moye moye !!! love from IITG

[@neerajgarg9096]

EAGERLY WAITING FOR THIS LECTURE LOVE U BABBAR BHAIYA❤❤

[@Coder_DhruvArora]

26:03 space complexity O(n) nahi hogi? As hum ek new list bana rahe hai

[@devanshbatra308]

Exactly, I am also confused with this.

[@RitikSingh-oh3sj]

merge walai second question mai maga aa gaya bhaiya

[@garimasharma276]

NEVER have I ever got such a crush on some one!! your way of teaching is quite captivating.

[@shripandey4120]

Bhaiya, 27:05 pr space complexity o(1) kse hogi, humne jo alag se three linked list bnayi hai uska space ?

[@alokranjan3185]

totatly different explanation bhaiya, thanks

[@yuvrajdhamija559]

1st question mein dummy nodes bnaane ki zaroorat hi kya thi?? uske bina bhi to ho jaayega code

[@riyadhossain1706]

Became a fan of your learning style...........

[@-akashkumarsingh]

Mere dekhne ki consistency se jyadaa toh video aane ki hai..

[@ayushp4471]

Your efforts BHAIYAA🔥🔥🙌🙌

[@sundrmm0350]

Bhiyaaaa!!! Uh beauty🙇🏻‍♂️

[@adityaraj-zm7zk]

bhai it is very good question and you really very good explained , fanstically you are very good teacher

[@theOmKumar]

Explanation + Minor adjustment to improve q1 while addressing memory leak! // // merge 3 sublist (assuming one's list is not empty) zeroTail -> next = oneHead -> next; oneTail -> next = twoHead -> next; twoTail -> next = NULL; return zeroHead -> next; //merge 3 sublist (Note: if 1st list is empty, then we can't connect zero list with two list using previous code) if (oneHead -> next != NULL) //one's list is not empty, so we'll connect 0 list with one { zeroTail -> next = oneHead -> next; oneTail -> next = twoHead -> next; } else zeroTail -> next = twoHead -> next; //one's list is empty, so we'll connect 0 list with 2s directly; twoTail -> next = NULL; //this will end the LL. return zeroHead -> next; // //to prevent memory leak, due to allocation of dummy node so we need to delete it. // Node* ans = zeroHead -> next; // delete(zeroHead); // delete(oneHead); // delete(twoHead); // return ans; }

[@lakshsinghania]

exactly! kudos

[@arpitghura]

this is what I am supposing as the oneHead does not have any one node, so if we put it outside it will create an additional LL which is of no use. So, we can put the line no. 60 inside the if condition to prevent the creation of additional LL.

[@tanishsinghal1879]

shi hai bhai agr tu comment m nhi likhta ye sb to mai ye sochta syad m hi glt hun

[@prashantmaurya6868]

Fantabulous explanation....

[@sachitdhamija1884]

bhaiya acha tha merge 2 sort L.L samjaha but sort 0,1,2 thoda problem hua but 2 baar aur dekho ga toh samjho ga lage raho

[@ritikamehta9791]

Great work sir!! mza aa rha hai ab pdhne me💯

[@rachit_joshi]

Thank You So Much BHRATA SHREE !!!!!

[@itzheavem4451]

very well explained Mzaa aa gya

[@ProgrammingPirates]

va bhayya moj kar di 🤩🤩🤩🤩🤩

[@satvikshukla596]

Thank you sir 🙏

[@vaibhavraj2847]

bhaiya aapne jo array me merge and sort wala concept se padhaya tha ussejyada easy se ho gaya!! #include #include using namespace std; class node { public: int data; node *next; node(int data) { this->data = data; this->next = NULL; } ~node() { int value = this->data; if (this->next != NULL) { next = NULL; } delete next; cout next = curr2; tail = curr2; curr2 = curr2->next; } } while (curr1 != NULL) { tail->next = curr1; tail = curr1; curr1 = curr1->next; } while (curr2 != NULL) { tail->next = curr2; tail = curr2; curr2 = curr2->next; } head = head->next; return head; } int main() { node *head1 = NULL, *head2 = NULL; node *tail1 = NULL, *tail2 = NULL; insert(1, head1, tail1); insert(3, head1, tail1); insert(5, head1, tail1); insert(8, head1, tail1); insert(2, head2, tail2); insert(4, head2, tail2); insert(5, head2, tail2); insert(8, head2, tail2); insert(10, head2, tail2); print(head1); print(head2); node *ans = merge_two(head1, head2); print(ans); }

[@amanmehra4368]

no words for you bhaiya ❤❤❤

[@theOmKumar]

Simpler Approach for Q2. , we can also do this without dummy node by putting head at right place first , and then simply traversing and joining smaller val data. ListNode* mergeTwoLists(ListNode* list1, ListNode* list2) { if (!list1) return list2; if (!list2) return list1; ListNode *ans = new ListNode(-1); ListNode *temp = ans; while (list1 && list2) { if (list1->val < list2->val) { temp -> next = list1; temp = list1; list1 = list1 -> next; } else { temp -> next = list2; temp = list2; list2 = list2 -> next; } } while (list1) { temp -> next = list1; temp = list1; list1 = list1 -> next; } while (list2) { temp -> next = list2; temp = list2; list2 = list2 -> next; } return ans -> next; }

[@kunalmodiart]

i watched the solution given in the video then went on to code the Q by myself with my approach .. then i came in comments to add my code and i found your code which is literally similar to mine 😂 what a coincidence

[@antrikshgupta1964]

void sort(Node* &tail, Node* &head){ tail->next = head; head = head->next; tail = tail->next; } //Function to merge two sorted linked list. Node* sortedMerge(Node* head1, Node* head2) { Node* head = new Node(-1); Node* tail = head; while(head1!=NULL and head2!=NULL){ if(head1->data data){ sort(tail,head1); } else{ sort(tail,head2); } } while(head1!=NULL){ sort(tail,head1); } while(head2!=NULL){ sort(tail,head2); } return head->next; }

[@adityachauhan5913]

@codeHelp bhaiya ek dummy node le kr compare aur direct connect karte chale jaaye last me dummy ka nxt return kar dnge

[@satyamjha-codeindwala6666]

Merge 2 Sorted Linked Lists || Sort 0s, 1s and 2s in Linked List🥰🥰🥰🥰🥰🥰🥰🥰

[@kundanmali2405]

thank you for providing such great content.

[@pahaljain9209]

Present sir

[@muneebjaved3940]

Thank you so much bhayia Concept ++++++; Explanation ++++++++;

[@suvigyabasnotra7378]

25:09 Now this code is giving Runtime Error (SIGSEGV) on each of the 3 test cases! Below is what I typed: void insertAtTail(Node* &tail, Node* curr){ tail -> next = curr; tail = curr; } Node* sortList(Node *head) { Node* zeroHead = new Node(-1); Node* zeroTail = zeroHead; Node* oneHead = new Node(-1); Node* oneTail = oneHead; Node* twoHead = new Node(-1); Node* twoTail = twoTail; Node* curr = head; // create separate linked lists for 0s, 1s and 2s. while(curr != NULL){ int value = curr -> data; if(value == 0){ insertAtTail(zeroTail, curr); } else if(value == 1){ insertAtTail(oneTail, curr); } else if(value == 2){ insertAtTail(twoTail, curr); } curr = curr -> next; } // merge 3 sublists //Case 1: linked list isn't empty if(oneHead -> next != NULL ){ zeroTail -> next = oneHead -> next; } else{ // list is empty zeroTail -> next = twoHead -> next; } oneTail -> next = twoHead -> next; twoTail -> next = NULL; // setup head head = zeroHead -> next; // deleting dummy nodes delete zeroHead; delete oneHead; delete twoHead; return head; }

[@04_abhishekpandey37]

bro Node* twoTail= twoHead hoga.

[@anuragpandey8165]

bro initialization of twoTail is not correct. It should be { Node* twoTail = twoHead; } and not { Node* twoTail = twoTail; }

[@suvigyabasnotra7378]

​@@anuragpandey8165 Checked the code at least thrice but couldn't find the error myself. Kamal karte hain Pandey ji!

[@suvigyabasnotra7378]

@@04_abhishekpandey37 ​ @Anurag Pandey Checked the code at least thrice but couldn't find the error myself. Kamal karte hain Pandey ji!

[@dhhforlife8889]

@@suvigyabasnotra7378 🤣🤣

[@muhammadsuleman8936]

Merge 2 Sorted Linked Lists || Sort 0s, 1s and 2s in Linked List

[@bhawargujral3574]

Great Video as usual.. Quality content

[@palaksolanki8037]

Thank you soooo much bhaiya for ur consistent efforts

[@prathmeshparteki1016]

Thanks for this great content bhaiyya .. 🤩

[@jatingarg1897]

Maza Aaayaa bhai karke !

[@shubhrasharma7282]

bhai... 2nd waala question leetcode pr TLE de rha hai..... aap aadhi conditions skip kr dete ho.....phir khud se condition add kr krke dimaag khraab hota hai

[@cg.yamangaming4632]

Bhaiya code studio me aap coding krte ho to list enter Karne vaala part samgh Ni as RHA kaise krna hai

[@B-NikhilRichhariya]

aap mehnat krte ho na wo dekh ke aur mehnat krne ka mn krta hai

[@anshulsingh1265]

done bhaiya

[@prathamSuthar-cy6hs]

Bhaiya yeh jo notes likhne ke liye software waparte ho yeh konsa he ??