Software Engineer

PROGRAM:

class Solution
{
public:
//Function to add two numbers represented by linked list.
Node*reverse(struct Node*head){
Node*curr=head;
Node*prev=NULL;
Node*nxt;
while(curr!=NULL){
nxt=curr->next;
curr->next=prev;
prev=curr;
curr=nxt;
}
return prev;
}
public:
struct Node* addTwoLists(struct Node* first, struct Node* second)
{
// code here
first=reverse(first);
second=reverse(second);
int c=0;
int s=0;
Node*temp;
Node*cur;
Node*res=NULL;


while(first!=NULL||second!=NULL){
s=c+(first?first->data:0)+(second?second->data:0);
if(s>9){
c=1;
}
else{
c=0;
}
s=s%10;
temp=new Node(s);
if(res==NULL)res=temp;
else{
cur->next=temp;
}
cur=temp;
if(first)first=first->next;
if(second)second=second->next;
}
if(c!=0){
temp=new Node(c);
cur->next=temp;
cur=temp;
}
res=reverse(res);
return res;
}
};

PROGRAM:

Node*merge(Node*a,Node*b){//a=root b=root ka right wala
if(a==NULL)return b;
if(b==NULL)return a;
Node*res;
if(a->datadata)
{
res=a;
res->bottom=merge(a->bottom,b);
}
else{
res=b;
res->bottom=merge(a,b->bottom);
}
res->next=NULL;
return res;
}
Node *flatten(Node *root)
{
if(root==NULL || root->next==NULL)return root;
return merge(root,flatten(root->next));
}

Tip 1 : Try to give answer with the real life examples
Tip 2 : Give answers in your own language and avoid the bookish language..