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062_FlattenALinkedList.cpp
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062_FlattenALinkedList.cpp
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#include<bits/stdc++.h>
using namespace std;
/****************************************************************
Following is the class structure of the Node class:
*****************************************************************/
class Node {
public:
int data;
Node* next;
Node* child;
Node(int data) {
this->data = data;
this->next = NULL;
this->child = NULL;
}
};
Node* merge(Node* L1, Node* L2) {
if(!L1){
return L2;
}
if(!L2){
return L1;
}
Node* result;
if(L1->data<L2->data){
result=L1;
result->child=merge(L1->child, L2);
}else{
result=L2;
result->child=merge(L1, L2->child);
}
result->next=NULL;
return result;
}
Node* flattenLinkedList(Node* head)
{
// Write your code here
if(!head || !head->next){
return head;
}
return merge(head, flattenLinkedList(head->next));
// Method-2 (gives TLE)
Node* curr=head;
vector<int> values;
while(curr){
values.push_back(curr->data);
if(curr->next){
Node* child=curr->child;
curr->child=curr->next;
Node* ptr=curr->child;
while(ptr->child){
ptr=ptr->child;
}
ptr->child=child;
curr->next=NULL;
}
curr=curr->child;
}
sort(values.begin(), values.end());
curr=head;
int i=0;
while(curr){
curr->data=values[i++];
curr=curr->child;
}
return head;
}