[002] delete_duplication_of_linked_list

[Description]Given a unsort Linked List, delete all the duplication from them, no temporary space permission.

[Thought]Set two points, from head to tail, scaning all linked list. O (N ^ 2 ).

[Implementation]C code:

 1 #include<stdio.h> 2  3 typedef struct linkedList 4 { 5         int data; 6         struct linkedList* next; 7 } llist; 8  9 llist** delDupli(llist **head)10 {11         // two point, t1 for target, t2 for mover.12         llist *t1, *t2;13         t1=t2=*head;14         while(t1->next != NULL)15         {16                 // ajust t2 from t1!17                 t2=t1;18                 while(t2->next != NULL)19                 {20                         // check if they are the same21                         if(t2->next->data == t1->data)22                         {23                                 // move t2->next; note: no memory free here.24                                 t2->next=t2->next->next;25                         }26                         // after move out node, check if t2 is already the last one.27                         if(t2->next != NULL)28                         {29                                 t2=t2->next;30                         }31                 }32                 t1=t1->next;33         }34         return head;35 }36 37 int addValue(llist **head, int val)38 {39 40         llist *pnode;41         llist *t=*head;42         // apply memory for linked list.43         pnode=(llist*)malloc(sizeof(llist));44         if(NULL==pnode)45         {46                 return 0;47         }48         pnode->data=val;49         pnode->next=NULL;50         // first node51         if(NULL==*head)52         {53                 *head=pnode;54                 return 1;55         }56         // move temp point to the last node57         while(t->next != NULL)58         {59                 t=t->next;60         }61         t->next=pnode;62         return 1;63 }64 65 // out put data, be careful about the first node.66 int printList(llist **head)67 {68         llist *t=*head;69         printf("%d, ",t->data);70         while(t->next != NULL)71         {72                 t=t->next;73                 printf("%d, ",t->data);74         }75         printf("\n");76         return 1;77 }78 79 int main()80 {81         int a[]={2,3,5,6,8,2,4,6,8,9,2,5,2};82         llist *head=NULL;83         int i;84 85         for(i=0;i<(sizeof(a)/sizeof(a[0]));i++)86         {87 //              printf("a[i]:%d\n",a[i]);88                 addValue(&head,a[i]);89 //              printList(&head);90         }91         printf("Initial linked list:\n");92         printList(&head);93         printf("After deleting:\n");94         printList(delDupli(&head));95 }

 

[002] delete_duplication_of_linked_list