82.c

#include<stdio.h>
#include<stdlib.h>

structListNode {
intval;
structListNode*next;
};

structListNode*deleteDuplicates(structListNode*head) {
if (head==NULL||head->next==NULL) returnhead;

structListNode*dummy=malloc(sizeof(structListNode));
dummy->val=0;
dummy->next=head;
structListNode*pre=dummy;
structListNode*p=dummy->next;
structListNode*q=dummy->next->next;

while (p&&q) {
if (p->val==q->val) {
pre->next=q->next;
 }
elseif (pre->next!=q) {
pre=pre->next;
 }
p=p->next;
q=q->next;
 }

structListNode*new_head=dummy->next;
free(dummy);

returnnew_head;
}

structListNode*buildList(int*nums, intnumsSize) {
if (numsSize==0) returnNULL;

structListNode*dummy=malloc(sizeof(structListNode));
dummy->val=0;
structListNode*p=dummy;
for (inti=0; i<numsSize; i++) {
p->next=malloc(sizeof(structListNode));
p->next->val=nums[i];
p=p->next;
 }
p->next=NULL;

p=dummy->next;
free(dummy);

returnp;
}

intmain() {

intnums[] = { 1, 2, 2, 2, 3, 3 };
structListNode*head=buildList(nums, sizeof(nums) / sizeof(nums[0]));
structListNode*p=head;
while (p) {
printf("%d->", p->val);
p=p->next;
 }
printf("NIL\n");

structListNode*new_head=deleteDuplicates(head);

p=new_head;
while (p) {
printf("%d->", p->val);
p=p->next;
 }
printf("NIL\n");

return0;
}