标签：nec node hid splay return nal pre oid 剑指offer
// 面试题18（一）：在O(1)时间删除链表结点 // 题目：给定单向链表的头指针和一个结点指针，定义一个函数在O(1)时间删除该 // 结点。 #include <cstdio> #include "List.h" void DeleteNode(ListNode** pListHead, ListNode* pToBeDeleted) { if (pListHead == nullptr || pToBeDeleted == nullptr) return; //多个节点, 且位于中间 if (pToBeDeleted->m_pNext != nullptr) { ListNode* pNext = pToBeDeleted->m_pNext; pToBeDeleted->m_nValue = pNext->m_nValue; pToBeDeleted->m_pNext = pNext->m_pNext; delete pNext; pNext = nullptr; } //单节点, else if (*pListHead == pToBeDeleted) { delete pToBeDeleted; pToBeDeleted = nullptr; *pListHead = nullptr; } //多节点, 处于尾部 else { ListNode* pNode = *pListHead; while (pNode->m_pNext != pToBeDeleted) pNode = pNode->m_pNext; pNode->m_pNext = nullptr; delete pToBeDeleted; pToBeDeleted = nullptr; } }
// ====================测试代码==================== void Test(ListNode* pListHead, ListNode* pNode) { printf("The original list is: \n"); PrintList(pListHead); printf("The node to be deleted is: \n"); PrintListNode(pNode); DeleteNode(&pListHead, pNode); printf("The result list is: \n"); PrintList(pListHead); } // 链表中有多个结点，删除中间的结点 void Test1() { ListNode* pNode1 = CreateListNode(1); ListNode* pNode2 = CreateListNode(2); ListNode* pNode3 = CreateListNode(3); ListNode* pNode4 = CreateListNode(4); ListNode* pNode5 = CreateListNode(5); ConnectListNodes(pNode1, pNode2); ConnectListNodes(pNode2, pNode3); ConnectListNodes(pNode3, pNode4); ConnectListNodes(pNode4, pNode5); Test(pNode1, pNode3); DestroyList(pNode1); } // 链表中有多个结点，删除尾结点 void Test2() { ListNode* pNode1 = CreateListNode(1); ListNode* pNode2 = CreateListNode(2); ListNode* pNode3 = CreateListNode(3); ListNode* pNode4 = CreateListNode(4); ListNode* pNode5 = CreateListNode(5); ConnectListNodes(pNode1, pNode2); ConnectListNodes(pNode2, pNode3); ConnectListNodes(pNode3, pNode4); ConnectListNodes(pNode4, pNode5); Test(pNode1, pNode5); DestroyList(pNode1); } // 链表中有多个结点，删除头结点 void Test3() { ListNode* pNode1 = CreateListNode(1); ListNode* pNode2 = CreateListNode(2); ListNode* pNode3 = CreateListNode(3); ListNode* pNode4 = CreateListNode(4); ListNode* pNode5 = CreateListNode(5); ConnectListNodes(pNode1, pNode2); ConnectListNodes(pNode2, pNode3); ConnectListNodes(pNode3, pNode4); ConnectListNodes(pNode4, pNode5); Test(pNode1, pNode1); DestroyList(pNode1); } // 链表中只有一个结点，删除头结点 void Test4() { ListNode* pNode1 = CreateListNode(1); Test(pNode1, pNode1); } // 链表为空 void Test5() { Test(nullptr, nullptr); } int main(int argc, char* argv[]) { Test1(); Test2(); Test3(); Test4(); Test5(); return 0; }
分析：代码假设要删除的节点的确在链表中。需要O(n)时间遍历链表才可以确认，可以讨论这个假设，考虑更为全面。
标签：nec node hid splay return nal pre oid 剑指offer
原文地址：https://www.cnblogs.com/ZSY-blog/p/12562615.html
