1、排序链表去重（保留一个）：
给定一个排序链表，删除重复元素，只保留重复元素中第一次出现的结点。
如：给定：3->4->5->6->6->6->7->8->8->9->10
返回：3->4->5->6->7->8->9->10
程序实现：
1 /************************************ 2 File Name:DeleteDuplicateNode.cpp 3 Author: godfrey 4 Created Time: 2016/04/29 5 *************************************/ 6 #include <iostream> 7 #include <cstdio> 8 #include <cstdlib> 9 using namespace std; 10 11 typedef struct tagSNode{ 12 int value; 13 tagSNode* pNext; 14 15 tagSNode(int v):value(v),pNext(NULL) {} 16 }SNode; 17 //打印链表 18 void Print(SNode* pHead){ 19 SNode* p = pHead->pNext; 20 while(p){ 21 cout<<p->value<<" "; 22 p = p->pNext; 23 } 24 cout<<endl; 25 } 26 //删除分配结点空间 27 void Destroy(SNode* pHead){ 28 SNode* p; 29 while(pHead){ 30 p = pHead->pNext; 31 delete pHead; 32 pHead = p; 33 } 34 } 35 //排序链表去重，重复元素保留第一次出现的元素 36 void DeleteDuplicateNode(SNode* pHead){ 37 SNode* pPre = pHead->pNext; 38 SNode* pCur = NULL; 39 while(pPre){ 40 pCur = pPre->pNext; 41 if(pCur && (pPre->value == pCur->value)){ 42 pPre->pNext = pCur->pNext; 43 delete pCur; 44 } 45 else{ 46 pPre = pCur; 47 } 48 } 49 } 50 int main() 51 { 52 SNode* pHead = new SNode(0); 53 int data[] = {3,4,5,6,6,6,7,8,8,9,10}; 54 int size = sizeof(data)/sizeof(int); 55 for(int i=size-1;i>=0;i--){ 56 SNode* p = new SNode(data[i]); 57 p->pNext = pHead->pNext; 58 pHead->pNext = p; 59 } 60 61 Print(pHead); 62 DeleteDuplicateNode(pHead); 63 Print(pHead); 64 Destroy(pHead); 65 return 0; 66 }
当然，同样的想法可以换一种编码形式，再额外使用一个结点：
1 //排序链表去重2，重复元素保留第一次出现的结点 2 void DeleteDuplicateNode2(SNode* pHead){ 3 SNode* pPre = pHead; 4 SNode* pCur = pHead->pNext; 5 SNode* t = NULL; 6 while(pCur){ 7 t = pCur->pNext; 8 while(t && (pCur->value == t->value)){ 9 pPre->pNext = t; 10 delete pCur; 11 pCur = t; 12 t = pCur->pNext; 13 } 14 pPre = pCur; 15 pCur = t; 16 } 17 }
两者运行结果相同，其为：
2、排序链表去重（全部删除）：
若题目变成，发现重复元素，则重复元素全部删除。
代码实现：
1 //排序链表去重3，删除所有的重复元素 2 void DeleteDuplicateNode3(SNode* pHead){ 3 SNode* pPre = pHead; 4 SNode* pCur = pHead->pNext; 5 SNode* t = NULL; 6 bool bDup;//重复标志位 7 while(pCur){ 8 t = pCur->pNext; 9 bDup = false; 10 while(t && (pCur->value == t->value)){ 11 pPre->pNext = t; 12 delete pCur; 13 pCur = t; 14 t = pCur->pNext; 15 bDup = true; 16 } 17 if(bDup){//pCur与原数据重复 18 pPre->pNext = t; 19 delete pCur; 20 } 21 else{//pCur没有重复，进行后移 22 pPre = pCur; 23 } 24 pCur = t; 25 } 26 }
运行结果为：
