刪除鏈表中重復的結點
阿新 • • 發佈：2017-08-19
describe image urn ati lis while null number nod 
1.加一個頭結點
2.兩個臨時指針p,q
3.找前後不相等的節點
題目描述
在一個排序的鏈表中，存在重復的結點，請刪除該鏈表中重復的結點，重復的結點不保留，返回鏈表頭指針。 例如，鏈表1->2->3->3->4->4->5 處理後為 1->2->5 1 遞歸/*
struct ListNode {
int val;
struct ListNode *next;
ListNode(int x) :
val(x), next(NULL) {
}
};
*/
class Solution {
public:
ListNode* deleteDuplication(ListNode* pHead)
{
if(pHead==NULL || pHead->next==NULL) return pHead;
while(pHead!=NULL && pHead->next!=NULL && pHead->val==pHead->next->val)
{
while(pHead!=NULL &&pHead->next!=NULL && pHead->val==pHead->next->val) {
pHead=pHead->next;
}
pHead=pHead->next;
}
if(pHead!=NULL) {
pHead->next=deleteDuplication(pHead->next);
}
return pHead;
}
};
2.
/*
struct ListNode {
int val;
struct ListNode *next;
ListNode(int x) :
val(x), next(NULL) {
}
};
*/
class Solution {
public:
ListNode* deleteDuplication(ListNode* pHead)
{
if(pHead == NULL || pHead->next==NULL) return pHead;
ListNode *HeadNode = new ListNode(-1);
HeadNode ->next = pHead;
ListNode *pveNode = HeadNode;
ListNode *p = HeadNode->next;
ListNode *nextNode = p->next;
while(p!=NULL && p->next!=NULL){
if(p->val == nextNode->val){
while(nextNode->next != NULL && nextNode->val == nextNode->next->val){
nextNode = nextNode->next;
}
p=nextNode->next;
nextNode = p->next;
pveNode->next = p;
}else{
pveNode = p;
p=nextNode;
nextNode = nextNode->next;
}
}
return HeadNode->next;
}
};
思路3：
1.加一個頭結點
2.兩個臨時指針p,q
3.找前後不相等的節點
class Solution {
public:
ListNode* deleteDuplication(ListNode* pHead)
{
if (pHead == NULL || pHead->next == NULL)
return pHead;
/*---------先為鏈表創建一個頭結點---------*/
int firstNumber = pHead->val;
//假設我的頭結點數值為-1
int myFirst = -1;
//萬一鏈表的頭結點也為-1，那麽我就改成-2
if (myFirst == firstNumber)
{
myFirst = -2;
}
ListNode *head = new ListNode(myFirst);
head->next = NULL;
head->next = pHead;
ListNode *p = head;
ListNode *q = head->next;
while (q)
{
while (q->next && (q->next->val == q->val))
{
q = q->next;
}
if (p->next != q)
{
q = q->next;
p->next = q;
}
else
{
p = q;
q = q->next;
}
}
//返回的時候，註意去掉頭結點（自己創建的輔助節點）
return head->next;
}
};
http://blog.csdn.net/eversliver/article/details/52234333
刪除鏈表中重復的結點