合并两个排序的链表

来源：互联网发布：淘宝购物数据流程图编辑：程序博客网时间：2024/04/30 05:09

合并两个排序的链表如：链表1:1->3->5->7; 链表2： 2->4->6->8; 合并结果为：1->2->3->4->5->6->7->8;

其合并策略类似于归并排序，这里实现了递归和非递归两种方式：

非递归合并：

ListNode* Merge(ListNode* pHead1, ListNode* pHead2){if( pHead1 == NULL )return pHead2;else if( pHead2 == NULL )return  pHead1;ListNode* pMergedHead = NULL;ListNode* p1 = pHead1;ListNode* p2 = pHead2;//找出最小的头结点if( p1->m_nValue < p2->m_nValue ){pMergedHead = p1;p1 = p1->m_pNext;}else{pMergedHead = p2;p2 = p2->m_pNext;}ListNode* pMerged = pMergedHead;while( (p1 != NULL) && (p2 != NULL) ){if( p1->m_nValue < p2->m_nValue ){pMerged->m_pNext = p1;pMerged = pMerged->m_pNext;p1 = p1->m_pNext;}else{pMerged->m_pNext = p2;pMerged = pMerged->m_pNext;p2 = p2->m_pNext;}}while( p1 != NULL ){pMerged->m_pNext = p1;pMerged = pMerged->m_pNext;p1 = p1->m_pNext;}while( p2 != NULL ){pMerged->m_pNext = p2;pMerged = pMerged->m_pNext;p2 = p2->m_pNext;}return pMergedHead;}

递归实现：

ListNode* Merge(ListNode* pHead1, ListNode* pHead2){    if(pHead1 == NULL)        return pHead2;    else if(pHead2 == NULL)        return pHead1;    ListNode* pMergedHead = NULL;    if(pHead1->m_nValue < pHead2->m_nValue)    {        pMergedHead = pHead1;        pMergedHead->m_pNext = Merge(pHead1->m_pNext, pHead2);    }    else    {        pMergedHead = pHead2;        pMergedHead->m_pNext = Merge(pHead1, pHead2->m_pNext);    }    return pMergedHead;}

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