合并两个有序链表
1.非递归方式
#include "stdafx.h" #include <iostream> using namespace std; struct ListNode { int m_nValue; ListNode *m_pNext; }; //合并两个有序链表,非递归方法 ListNode *MergeTwoList(ListNode *pListOneHead, ListNode *pListTwoHead) { if (pListOneHead == NULL) { return pListTwoHead; } if (pListTwoHead == NULL) { return pListOneHead; } ListNode *pNode1 = pListOneHead; ListNode *pNode2 = pListTwoHead; ListNode *pMergeListHead = NULL; ListNode *pCurLastNode = NULL; if (pNode1->m_nValue < pNode2->m_nValue) { pMergeListHead = pListOneHead; pNode1 = pNode1->m_pNext; pCurLastNode = pMergeListHead; } else { pMergeListHead = pListTwoHead; pNode2 = pNode2->m_pNext; pCurLastNode = pMergeListHead; } while (pNode1 != NULL && pNode2 != NULL) { if (pNode1->m_nValue < pNode2->m_nValue) { pCurLastNode->m_pNext = pNode1; pCurLastNode = pNode1; pNode1 = pNode1->m_pNext; } else { pCurLastNode->m_pNext = pNode2; pCurLastNode = pNode2; pNode2 = pNode2->m_pNext; } if (pNode1 == NULL) { pCurLastNode->m_pNext = pNode2; } if (pNode2 == NULL) { pCurLastNode->m_pNext = pNode1; } } return pMergeListHead; } //创建一个链表,输入从头到尾结点的值,输入-1表示结束 void CreateList(ListNode *& pHead) { ListNode *pListNode = NULL; ListNode *pCurLastNode = NULL; bool isHead = true; while (1) { if (isHead) { pHead = new ListNode(); cin >> pHead->m_nValue; if (pHead->m_nValue == -1) { pHead = NULL; break; } pHead->m_pNext = NULL; isHead = false; pCurLastNode = pHead; } else { pListNode = new ListNode(); cin >> pListNode->m_nValue; if (pListNode->m_nValue == -1) { break; } pListNode->m_pNext = NULL; pCurLastNode->m_pNext = pListNode; pCurLastNode = pListNode; } } } //从头到尾打印链表 void PrintList(ListNode *&pHead) { if (pHead != NULL) { ListNode *pCur = pHead; while (pCur != NULL) { cout << pCur->m_nValue << " "; pCur = pCur->m_pNext; } cout << endl; } else { cout << "链表为空!" << endl; } } int _tmain(int argc, _TCHAR* argv[]) { ListNode *pList1Head = NULL; CreateList(pList1Head); PrintList(pList1Head); ListNode *pList2Head = NULL; CreateList(pList2Head); PrintList(pList2Head); ListNode *pMergeListHead = MergeTwoList(pList1Head, pList2Head); if (pMergeListHead != NULL) { cout << pMergeListHead->m_nValue << endl; } PrintList(pMergeListHead); system("pause"); return 0; }
2.递归方式
#include "stdafx.h" #include <iostream> using namespace std; struct ListNode { int m_nValue; ListNode *m_pNext; }; //合并两个有序链表,递归方法 ListNode *MergeTwoList(ListNode *pListOneHead, ListNode *pListTwoHead) { if (pListOneHead == NULL) { return pListTwoHead; } if (pListTwoHead == NULL) { return pListOneHead; } ListNode *pMergeListHead = NULL; if (pListOneHead->m_nValue < pListTwoHead->m_nValue) { pMergeListHead = pListOneHead; pMergeListHead->m_pNext = MergeTwoList(pMergeListHead->m_pNext, pListTwoHead); } else { pMergeListHead = pListTwoHead; pMergeListHead->m_pNext = MergeTwoList(pListOneHead, pMergeListHead->m_pNext); } return pMergeListHead; } //创建一个链表,输入从头到尾结点的值,输入-1表示结束 void CreateList(ListNode *& pHead) { ListNode *pListNode = NULL; ListNode *pCurLastNode = NULL; bool isHead = true; while (1) { if (isHead) { pHead = new ListNode(); cin >> pHead->m_nValue; if (pHead->m_nValue == -1) { pHead = NULL; break; } pHead->m_pNext = NULL; isHead = false; pCurLastNode = pHead; } else { pListNode = new ListNode(); cin >> pListNode->m_nValue; if (pListNode->m_nValue == -1) { break; } pListNode->m_pNext = NULL; pCurLastNode->m_pNext = pListNode; pCurLastNode = pListNode; } } } //从头到尾打印链表 void PrintList(ListNode *&pHead) { if (pHead != NULL) { ListNode *pCur = pHead; while (pCur != NULL) { cout << pCur->m_nValue << " "; pCur = pCur->m_pNext; } cout << endl; } else { cout << "链表为空!" << endl; } } int _tmain(int argc, _TCHAR* argv[]) { ListNode *pList1Head = NULL; CreateList(pList1Head); PrintList(pList1Head); ListNode *pList2Head = NULL; CreateList(pList2Head); PrintList(pList2Head); ListNode *pMergeListHead = MergeTwoList(pList1Head, pList2Head); if (pMergeListHead != NULL) { cout << pMergeListHead->m_nValue << endl; } PrintList(pMergeListHead); system("pause"); return 0; }