Remove Duplicates from Sorted List II

class Solution {

public:

ListNode* deleteDuplicates(ListNode* head) {

ListNode *head1=head ,*p,*pre=head;

int i,count=0;

if(head==NULL||head->next==NULL) return head;

while(head->next->val==head->val)

{ i=head->val;

while(i==head->val&&head->next!=NULL)

{

head=head->next;

count=1;

} //找出头结点，把头结点重复的都删掉。

if(count==1&&head->val==i) return NULL;

// if(head->next==NULL) return NULL;

if(head->next==NULL) return head; //判断是否头结点后面就只剩一个元素

}

head1=head; //重新开始找

if(count==1) pre=head;

//if(head->next!=NULL&&count==1) head=head->next;

while(head1->next!=NULL&&head1->next->next!=NULL) //最后就会剩一个元素

{

if(head1->next->val==head1->val) //相等的话保存值继续找

{

i=head1->val;

// flag=1;

head1=head1->next->next;

while(i==head1->val&&head1->next!=NULL)

{ head1=head1->next;} //找出不等的

if(head1->next!=NULL&&head1->next->val!=head1->val) //接上新的头结点

{

head->next=head1;

head=head->next;

}

if(head1->next==NULL&&head1->val==i) 判断是否结束

head->next=NULL;

// else head->next=head1;

if(head1->next==NULL&&head1->val!=i)

head->next=head1;

}

else {

head1=head1->next;

if(head1->next!=NULL&&head1->next->val!=head1->val) 要判断是否该接入。

{

head->next=head1;

head=head->next;

}

// head1=head1->next;

}

}

if(head1->next!=NULL&&(head1->val==head1->next->val))

{ head->next=NULL;}

return pre;

}

};

int main() {

Solution solution;

int A[] = {1,2,2,3};

//int B[] = {5,6,4};

int i;

ListNode *head = NULL;

ListNode *head1 = (ListNode*)malloc(sizeof(ListNode));

ListNode *head2 = (ListNode*)malloc(sizeof(ListNode));

head1->next = NULL;

head2->next = NULL;

ListNode *node;

ListNode *pre = head1;

for(int i = 0;i <=3;i++){

node = new ListNode(0);

node->val= A[i];

node->next = NULL;

pre->next = node;

pre = node;

}

//for(int i = 0;i <=0;i++){

// node = new ListNode(1);

// // node->exp = A[i];

// node->next = NULL;

// pre->next = node;

// pre = node;

// }

// for(int i = 0;i <=1;i++){

// node = new ListNode(2);

// // node->exp = A[i];

// node->next = NULL;

// pre->next = node;

// pre = node;

// }

//for(int i = 0;i <=2;i++){

// node = new ListNode(3);

// // node->exp = A[i];

// node->next = NULL;

// pre->next = node;

// pre = node;

// }

// // pre = head2;

// //for(int i = 2;i < 5;i++){

// // node = new ListNode(4);

// // // node->val = B[i];

// // node->next = NULL;

// // pre->next = node;

// // pre = node;

// //}

head = solution.deleteDuplicates(head1->next);

while(head != NULL){

// printf("%d %d ",head->coef,head->exp);

cout<<head->val<<' ';

head = head->next;

}

//i=(head1->val);

//cout<<i;

return 0;

}

满纸荒唐言，一把辛酸泪啊。花了我快三天。