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题目要求：
Given a sorted linked list, delete all duplicates such that each element appear only once.
For example,
Given 1->1->2, return 1->2.
Given 1->1->2->3->3, return 1->2->3.
这道题不难。具体程序如下：
1 /** 2 * Definition for singly-linked list. 3 * struct ListNode { 4 * int val; 5 * ListNode *next; 6 * ListNode(int x) : val(x), next(NULL) {} 7 * }; 8 */ 9 class Solution { 10 public: 11 ListNode* deleteDuplicates(ListNode* head) { 12 if(!head || !head->next) 13 return head; 14 15 int preVal = head->val; 16 ListNode *preNode = head; 17 ListNode *start = head->next; 18 while(start) 19 { 20 while(start && start->val == preNode->val) 21 { 22 ListNode *next = start->next; 23 preNode->next = next; 24 delete start; 25 start = next; 26 } 27 28 if(!start) 29 break; 30 31 preNode = start; 32 start = start->next; 33 } 34 35 return head; 36 } 37 };
题目要求：
Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.
For example,
Given 1->2->3->3->4->4->5, return 1->2->5.
Given 1->1->1->2->3, return 2->3.
该题可以通过添加dummy节点以方便编程。具体程序如下：
1 /** 2 * Definition for singly-linked list. 3 * struct ListNode { 4 * int val; 5 * ListNode *next; 6 * ListNode(int x) : val(x), next(NULL) {} 7 * }; 8 */ 9 class Solution { 10 public: 11 ListNode* deleteDuplicates(ListNode* head) { 12 if(!head || !head->next) 13 return head; 14 15 int preVal = head->val; 16 ListNode *dummy = new ListNode(0); 17 dummy->next = head; 18 ListNode *prepreNode = dummy, *preNode = head; 19 ListNode *start = head->next; 20 while(start) 21 { 22 bool flag = true; 23 while(start && start->val == preNode->val) 24 { 25 flag = false; 26 ListNode *next = start->next; 27 preNode->next = next; 28 delete start; 29 start = next; 30 } 31 32 if(flag) 33 { 34 prepreNode = preNode; 35 preNode = preNode->next; 36 } 37 else 38 { 39 prepreNode->next = preNode->next; 40 delete preNode; 41 preNode = prepreNode->next; 42 } 43 44 if(!preNode || !preNode->next) 45 break; 46 start = preNode->next; 47 } 48 49 head = dummy->next; 50 delete dummy; 51 dummy = nullptr; 52 53 return head; 54 } 55 };
LeetCode之“链表”：Remove Duplicates from Sorted List && Remove Duplicates from Sorted List II
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原文地址：http://www.cnblogs.com/xiehongfeng100/p/4602536.html
