链表划分：
给定一个链表和一个值key，将链表划分成两部分，使得划分后小于key的结点在前，大于key的结点在后。在上述两部分中要保持链表中的出现顺序。
如：给定：1->4->3->2->5->2 和 key = 3.
返回：1->2->2->4->3->5.
程序实现：
1 /************************************ 2 File Name:ListPartition.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 //链表划分 36 void ListPartition(SNode* pHead,int key){ 37 //使用链表分别存储小于key，大于key的数值 38 SNode* p1Head = new SNode(0); 39 SNode* p2Head = new SNode(0); 40 //两个链表当前最后一个元素 41 SNode* p1Tail = p1Head; 42 SNode* p2Tail = p2Head; 43 SNode* p = pHead->pNext; 44 //遍历原链表 45 while(p){ 46 if(p->value < key){ 47 p1Tail->pNext = p; 48 p1Tail = p; 49 } 50 else{ 51 p2Tail->pNext = p; 52 p2Tail = p; 53 } 54 p = p->pNext; 55 } 56 //将p2链表拼接到p1链表尾部 57 p1Tail->pNext = p2Head->pNext; 58 p2Tail->pNext = NULL; 59 //将拼接好的链表赋值给原链表 60 pHead->pNext = p1Head->pNext; 61 62 delete p1Head; 63 delete p2Head; 64 } 65 66 int main() 67 { 68 SNode* pHead = new SNode(0); 69 for(int i=0;i<10;i++){ 70 SNode* p = new SNode(rand()%100); 71 p->pNext = pHead->pNext; 72 pHead->pNext = p; 73 } 74 75 Print(pHead); 76 ListPartition(pHead,50); 77 Print(pHead); 78 Destroy(pHead); 79 return 0; 80 }
运行结果：
