非常齐全的链表操作

//无头结点单链表的各类操作#include #include #include using namespace std;struct LinkList {int value;LinkList *next;};//根据输入建立单链表：链表头部插入LinkList *BuildList() {LinkList *head = NULL;int data;int i = 0;while (scanf("%d", &data) != EOF) {//scanf("%d", &data);++i;LinkList *new_node = (LinkList *)malloc(sizeof(LinkList));if (NULL == new_node) {fprintf(stderr, "malloc failed");return head;}new_node->value = data;if (head == NULL) {new_node->next = NULL;head = new_node;}else {new_node->next = head;head = new_node;}}return head;}//在链表头部插入节点LinkList *InsertToHead(int value, LinkList *head) {LinkList *new_node = (LinkList *)malloc(sizeof(LinkList));if (new_node == NULL) {fprintf(stderr, "malloc failed");return head;}new_node->value = value;new_node->next = NULL;if (head == NULL) {head = new_node;}else {new_node->next = head;head = new_node;}return head;}//链表尾部插入节点LinkList *InsertToTail(int value, LinkList *head) {LinkList *new_node = (LinkList *)malloc(sizeof(LinkList));if (new_node == NULL) {fprintf(stderr, "malloc failed");return head;}new_node->value = value;new_node->next = NULL;if (head == NULL)head = new_node;else {LinkList *pnode = head;while (pnode->next != NULL)pnode = pnode->next;pnode->next = new_node;}return head;}//删除某节点LinkList *DeletebyValue(int value, LinkList* head) {if (head == NULL)return head;LinkList *pToDelete = NULL;if (head->value == value) {pToDelete = head;head = head->next;}else {LinkList *p = head;while (p->next != NULL && p->next->value != value)p = p->next;if (p->next != NULL) {pToDelete = p->next;p->next = pToDelete->next;}}if (pToDelete != NULL) {free(pToDelete);pToDelete = NULL;}return head;}unsigned int Length(LinkList *head) {unsigned int length = 0;LinkList *p = head;while (p) {++length;p = p->next;}return length;}//打印单链表void PrintList(LinkList *head) {LinkList *p = head;while (p) {printf("%d ", p->value);p = p->next;}printf("\n");}//逆序打印单链表：非递归void RPrintList(LinkList* head) {if (NULL == head)return;stack list_stack;while (head) {list_stack.push(head->value);head = head->next;}while (!list_stack.empty()) {printf("%d ", list_stack.top());list_stack.pop();}printf("\n");}//逆序打印单链表：递归void RPrintListRecursively(LinkList* head) {if (NULL == head)return;else {RPrintListRecursively(head->next);printf("%d ", head->value);}}//冒泡排序单链表LinkList* Sort(LinkList *head) {if (NULL == head)return head;int length = Length(head);int unorder_size = length;int flag = 1;while (flag) {flag = 0;LinkList *p = head;for (int i = 0; p->next && i < unorder_size; ++i) {if (p->value > p->next->value) {int temp = p->value;p->value = p->next->value;p->next->value = temp;flag = 1;}p = p->next;} --unorder_size;}return head;}//翻转单链表LinkList* ReverseList(LinkList *head) {//其实这里if判断当链表节点个数小于两个的情况//不是必须的，因为之后的程序包含这里的判断if (NULL == head || NULL == head->next){return head;}LinkList *reverse_head = NULL; //翻转后链表的头指针LinkList *pcurrent = head; //pcurrent遍历链表while (pcurrent) {LinkList* temp = pcurrent;pcurrent = pcurrent->next;temp->next = reverse_head;reverse_head = temp;}return reverse_head;}//找出链表倒数第k个节点（k > 0)LinkList * GetRKthNode(LinkList *head, int k) {if (k < 1 || NULL == head)return NULL;LinkList *first = head;LinkList *second = head;//如果节点个数小于k返回NULLfor (int i = 1; i < k; ++i) {if (second->next)second = second->next;elsereturn NULL;}//两个指针同时移动，直到快的second指针走到最后一个节点，//此时慢的first指针指向的就是倒数第k个节点while (second->next != NULL) { first = first->next;second = second->next;}return first;}//返回单链表的中间节点，当链表节点个数为偶数时//该函数返回链表第n/2 + 1个节点LinkList *GetMiddleNode (LinkList* head) {//链表为空或者仅有一个节点if (NULL == head || NULL == head->next)return head;LinkList *first = head;LinkList *second = head;while (second->next) {first = first->next;second = second->next;if (second->next) { //当节点个数为偶数时情况比较特殊second = second->next;}}return first;}//合并两个有序的单链表：非递归//链表原来相等的元素都保留LinkList* MergeList(LinkList* heada, LinkList *headb) {if (NULL == heada)return headb;if (NULL == headb)return heada;LinkList *head_merge = NULL;//比较第一个节点大小，取小者作为合并后第一个节点if (heada->value <= headb->value) {head_merge = heada;//注意下面两条语句顺序不能换，否则heada将指向空heada = heada->next;}else {head_merge = headb;//注意下面两条语句顺序不能换，否则headb将指向空headb = headb->next;//head_merge->next = NULL;}head_merge->next = NULL;LinkList *pmerge = head_merge;while(heada != NULL && headb != NULL) {if (heada->value <= headb->value) {pmerge->next = heada;heada = heada->next;pmerge = pmerge->next;}else {pmerge->next = headb;headb = headb->next;pmerge = pmerge->next;}pmerge->next = NULL;}if (heada)pmerge->next = heada;else if (headb)pmerge->next = headb;return head_merge;}//合并两个有序的单链表：递归//链表原来相等的元素都保留LinkList* MergeListRecursively(LinkList *heada, LinkList *headb) {if (NULL == heada)return headb;if (NULL == headb)return heada;LinkList *head_merge = NULL;if (heada->value <= headb->value) {head_merge = heada;head_merge->next = MergeListRecursively(heada->next, headb);}else {head_merge = headb;head_merge->next = MergeListRecursively(heada, headb->next);}return head_merge;}//判断链表中是否有环bool HasCircle(LinkList *head) {if (NULL == head)return false;LinkList *first = head;LinkList *second = head;while (first && second->next) {second = second->next->next;first = first->next;if (first == second)return true;}return false;}//判断两个链表是否相交bool IsCross(LinkList* heada, LinkList *headb) {if (NULL == heada || NULL == headb)return false;LinkList* taila = heada;LinkList* tailb = headb;while (taila->next)taila = taila->next;while (tailb->next)tailb = tailb->next;return taila == tailb;}//找出两个链表相交的第一个节点LinkList* GetFirstCrossNode(LinkList* heada, LinkList* headb) {if (NULL == heada || NULL == headb)return NULL;int lengtha = 1;LinkList* taila = heada;while (taila->next) {++lengtha;taila = taila->next;}int lengthb = 1;LinkList* tailb = headb;while (tailb->next) {++lengthb;tailb = tailb->next;}//两个链表没有相交if (taila != tailb)return NULL;LinkList* plong = heada; //指向长度大的链表LinkList* pshort = headb;//指向长度小的链表int diff;if (lengthb > lengtha) {diff = lengthb - lengtha;plong = headb;pshort = heada;}//长链表先向前走，使得两个链表对齐for (int i = 0; i < diff; ++i)plong = plong->next;while (plong && pshort && plong != pshort) {plong = plong->next;pshort = pshort->next;}return plong;}//已知链表存在环，求进入链表的第一个节点LinkList* GetFirstCircleNode(LinkList* head) {if (NULL == head)return NULL;//判断两个链表是否有环，没环返回空LinkList *first = head;LinkList *second = head;while (first && second->next) {first = first->next;second = second->next->next;if (first == second)break;}if (NULL == first || NULL == second->next)return NULL;//将相遇时环中的这个节点作为假设的尾节点，//就将原链表变为两个相交的单链表，第一个公共结点即为所求LinkList* assumed_tail = first;LinkList* head1 = head;LinkList* head2 = assumed_tail->next;LinkList *pa = head1;int length1 = 1;while (pa != assumed_tail) {pa = pa->next;++length1;}LinkList* pb = head2;int length2 = 1;while (pb != assumed_tail) {pb = pb->next;++length2;}pa = head1;pb = head2;if (length1 > length2) {int diff = length1 - length2;while (diff--)pa = pa->next;}else {int diff = length2 - length1;while (diff--)pb = pb->next;}while (pa != pb) {pa = pa->next;pb = pb->next;}return pa;}//删除某个指针指向的结点，时间复杂度O(1)void DeleteTheNode(LinkList *head, LinkList *to_delete) {if (NULL == to_delete || NULL == head)return;//要删除的是最后一个结点if (NULL == to_delete->next) {if (head == to_delete) { //要删除的是链表仅有的一个结点head = NULL;free(to_delete);to_delete = NULL; //防止垂悬指针}else { //链表有多个结点，要删除尾结点LinkList* p = head;while (p->next != to_delete)p = p->next;p->next = NULL;free(to_delete);to_delete = NULL; //防止垂悬指针}} else { //要删除的不是尾结点LinkList *pnext = to_delete->next;to_delete->value = pnext->value;to_delete->next = pnext->next;free(pnext);pnext = NULL;}}int main() {/*LinkList *head = BuildList();head = InsertToHead(9, head);head = InsertToTail(100, head);head = DeletebyValue(2, head);printf("length: %d\n", Length(head));PrintList(head);head = Sort(head);printf("list1: ");PrintList(head);*//*head = ReverseList(head);PrintList(head);*//*LinkList* kth = GetRKthNode(head, 1);if (kth)printf("1th：%d\n", kth->value);*//*LinkList *mid = GetMiddleNode(head);if (mid)printf("mid : %d\n", mid->value);*//*RPrintListRecursively(head);printf("\n");RPrintList(head);*///LinkList *head = BuildList();//LinkList *headb = BuildList();//printf("list2: ");PrintList(headb);//LinkList *head_merge = MergeList(head, headb);////LinkList *head_merge = MergeListRecursively(head, headb);//printf("list merge: ");PrintList(head_merge);/*//LinkList* head = (LinkList*)malloc(sizeof(LinkList));//head->next = head;LinkList *head = BuildList();LinkList *temp = head;while (temp->next)temp = temp->next;temp->next = head;if (HasCircle(head)) {printf("yes\n");}elseprintf("no\n");*//*LinkList *head = BuildList();LinkList *temp = head;while (temp->next)temp = temp->next;LinkList* headb = BuildList();temp->next = headb->next->next;LinkList* p = GetFirstCrossNode(head, headb);if (p)printf("%d\n", p->value);*/}