#include<iostream> #include<assert.h> using namespace std; struct node {     int val;     node * next;     node(int v)     {         val=v;         next=NULL;     } }; node * merge(node* list1 , node * list2) {     assert(list1!=NULL&&list2!=NULL);     node * res;     if(list1->val<=list2->val)     {         res=list1;         list1=list1->next;     }     else     {         res=list2;         list2=list2->next;     }     node * p = res;     node *p1 =list1,*p2 =list2;     while(p1!=NULL&&p2!=NULL)     {         if(p1->val<=p2->val)         {             p->next=p1;             p=p->next;             p1=p1->next;         }         else         {             p->next=p2;             p=p->next;             p2=p2->next;         }     }     while(p1!=NULL)     {         p->next=p1;         p=p->next;         p1=p1->next;     }     while(p2!=NULL)     {         p->next=p2;         p=p->next;         p2=p2->next;     }     return res; } int * merge(int * arr1,int la, int * arr2,int lb) {     int i=0,j=0;     int * arr = new int[la+lb];     int t=0;     while(i<la&&j<lb)     {         if(arr1[i]<=arr2[j])         {             arr[t++]=arr1[i];             i++;         }         else         {             arr[t++]=arr2[j];             j++;         }     }     while(i<la)     {         arr[t++]=arr1[i];         i++;     }     while(j<lb)     {         arr[t++]=arr2[j];         j++;     }     return arr; } void setLinkData(node * & list1 , node * & list2) {     node * node1 = new node(2);     node * node2 = new node(3);     node * node3 = new node(7);     node * node4= new node(9);     node1->next=node2;     node2->next=node3;     node3->next=node4;     list1=node1;     node * node5 = new node(1);     node * node6 = new node(4);     node * node7 = new node(6);     node * node8 = new node(8);     node5->next=node6;     node6->next=node7;     node7->next=node8;     list2=node5; } int main() {     node * list1;     node * list2;     setLinkData(list1,list2);     int arr1[]={1,6,15,17,19};     int arr2[]={2,4,6,8,10};     int * arr = merge(arr1,5,arr2,5);     node * ans = merge(list1,list2);     //Print result     int length=10;     for(int i=0;i<10;i++)     {         cout<<*arr<<endl;         arr++;     }     while(ans!=NULL)     {         cout<<ans->val<<endl;         ans=ans->next;     }     return 0; }