每日一题(91) - 插入排序

题目来自网络

题目(1)：基于数组的插入排序

思路：总是把待排序元素插入已排序的元素集合中，程序的重点是查找待排序元素的位置。

查找待排序元素的位置时，

对于数组，既可以从前往后找，也可以由后往前找。

对于链表，可以从前往后找。

代码：

void InsertSort(int nArr[],int nLen){int j = 0;for (int i = 2;i <= nLen;i++){if (nArr[i] < nArr[i - 1]){nArr[0] = nArr[i];j = i - 1;while(nArr[0] < nArr[j]){nArr[j + 1] = nArr[j];j--;}nArr[j + 1] = nArr[0];}}}

题目(2)：基于链表的插入排序

思路：基于链表的插排，可以看成一个旧链表中的一个结点要插入到一个新链表的结点中。

代码：

#include <iostream>using namespace std;struct ListNode{int m_nData;ListNode* pNext;};void InsertSort(ListNode*& pHead){ListNode* pCurOld = pHead;ListNode* pCurOldNext = pHead;ListNode* pCurNew = pHead;ListNode* pLast = NULL;pHead = NULL;while(pCurOld != NULL){pCurOldNext = pCurOld -> pNext;if (pHead == NULL){pCurOld->pNext = pHead;pHead = pCurOld;pLast = pCurOld;}else if (pHead->m_nData > pCurOld->m_nData){pCurOld->pNext = pHead;pHead = pCurOld;}else if (pLast->m_nData <= pCurOld->m_nData){pLast->pNext = pCurOld;pCurOld->pNext = NULL;pLast = pCurOld;}else{pCurNew = pHead;while(pCurNew->pNext->m_nData < pCurOld->m_nData){pCurNew = pCurNew->pNext;}pCurOld->pNext = pCurNew->pNext;pCurNew->pNext = pCurOld;}pCurOld = pCurOldNext;}}void Print(ListNode* pHead){while(pHead != NULL){cout<<pHead->m_nData<<" ";pHead = pHead->pNext;}cout<<endl;}void CreateList(ListNode** pHead,int nLen)//头指针使用指针的指针  {  ListNode* pCur = NULL;  ListNode* pNewNode = NULL;  for (int i = 0;i < nLen;i++)  {  pNewNode = new ListNode;  cin>>pNewNode->m_nData;  pNewNode->pNext = NULL;  if (*pHead == NULL)  {  *pHead = pNewNode;  pCur = *pHead;  }  else  {  pCur->pNext = pNewNode;  pCur = pNewNode;  }  }  }  int main(){int nLen = 4;ListNode* pHead = NULL;CreateList(&pHead,nLen);InsertSort(pHead);Print(pHead);system("pause");return 1;}