2-5编写算法，在单链表中查找第一值为x的结点，并输出其前驱和后继的存储位置

#include<stdio.h>
#include<stdlib.h>typedef int DataType; 
struct Node
{DataType      data; struct Node*  next;  
};
typedef struct Node  *PNode;    
typedef struct Node  *LinkList;   LinkList SetNullList_Link() //设置头结点
{LinkList head = (LinkList)malloc(sizeof(struct Node));if (head != NULL) head->next = NULL;else printf("alloc failure");return head; 
}void CreateList_Tail(struct Node* head)//利用尾插法
{PNode p = NULL;PNode q = head;DataType data;scanf("%d", &data);while (data != -1){   p = (struct Node*)malloc(sizeof(struct Node));p->data = data;p->next = NULL;q->next = p;q = p;scanf("%d", &data);}
}
int Inserch_num(LinkList head,int x)//找值 
{LinkList p;int i=0;p=head->next;while(p)//把前后特殊情况单列出来 {if(i==0&&p->data==x){printf("The Prodrove node is head,the position of the rear  node is at position 2 of the linked list\n");return 0;}if(p->data==x&&p->next==NULL){printf("The Prodrove node is %d,there is no rear node\n ",i);return 0;}if(p->data==x){printf("The Prodrove node is %d,he rear node is %d\n",i,i+2); return 0;}i++;p = p->next;}return 0;
}
void print(LinkList head)   //打印
{PNode  p = head->next;while (p){printf("%d ", p->data);p = p->next;}
}
void DestoryList_Link(LinkList head)  //销毁链表
{PNode  pre = head; PNode p = pre->next;while (p){free(pre);pre = p;p = pre->next;}free(pre);
}int main()
{LinkList head = NULL;int x=0,a=0;head = SetNullList_Link();CreateList_Tail(head);print(head);printf("\n");printf("Please input the number you find:");scanf("%d",&x);a=x;Inserch_num(head,a);DestoryList_Link(head);return 0;
}

2-6在单循环链表中，编写算法实现将链表中数据域为奇数的结点移至表头，将链表中数据域为偶数的结点移至表尾

#include<stdio.h>
#include<stdlib.h>typedef int DataType; 
struct Node {DataType      data; struct Node*  next;  
};
typedef struct Node  *PNode;    
typedef struct Node  *LinkList;   LinkList CreateList_Tail_loop()
{LinkList head = (LinkList)malloc(sizeof(struct Node));PNode cur = NULL;PNode tail = head;DataType data;scanf("%d", &data);while (data != -1){   cur = (struct Node*)malloc(sizeof(struct Node));cur->data = data;tail->next = cur;tail = cur;scanf("%d", &data);}tail->next = head;return tail;
}
PNode Move_Odd_Even(LinkList tail)
{PNode head=tail->next,pre=head->next,q=pre->next;PNode pre1,head1=(PNode)malloc(sizeof(struct Node));PNode pre2,head2=(PNode)malloc(sizeof(struct Node));pre1=head1;pre2=head2;while(q!=head->next){if(pre->data%2==0){pre->next=pre1->next;pre1->next=pre;pre1=pre;}else{pre->next=pre2;pre2->next=pre;pre2=pre;}pre=q;q=q->next;}
head1=head1->next;
pre2->next=head1;
pre1->next=head2;
return pre1;
}
void print(LinkList tail)    
{PNode  head = tail->next;PNode p = head->next;while (p != head){printf("%d ", p->data);p = p->next;}
}void DestoryList_Link(LinkList tail)
{PNode pre = tail->next;PNode p = pre->next;while (p != tail){free(pre);pre = p;p = pre->next;}free(pre);free(tail);
}int main()
{LinkList tail = NULL;LinkList p = NULL;tail = CreateList_Tail_loop();p = Move_Odd_Even(tail);print(p);DestoryList_Link(tail);return 0;
}

2-7将两个有序线性表LIST1=（a1,a2,…，an）和LIST2=（b1,b2,…,bn）链接成一个有序线性链表LIST3,并删除LIST3链表中相同的结点，即链接中若有多个结点具有相同的数据域，只保留一个结点，使得顺序表中所有结点的数据域都不相同。在采用顺序表和单链表两种形式下分别设计算法实现上述功能

#include <stdio.h>
#include <stdlib.h>#define MAX_SIZE 100void mergeAndRemoveDuplicates(int list1[], int list2[], int n1, int n2, int list3[]) {int i = 0, j = 0, k = 0;while (i < n1 && j < n2) {if (list1[i] < list2[j]) {list3[k] = list1[i];i++;k++;} else if (list1[i] > list2[j]) {list3[k] = list2[j];j++;k++;} else {  // 相同元素list3[k] = list1[i];i++;j++;k++;}}while (i < n1) {list3[k] = list1[i];i++;k++;}while (j < n2) {list3[k] = list2[j];j++;k++;}
}void removeDuplicates(int list[], int size) {int i, j, k;for (i = 0; i < size; i++) {for (j = i + 1; j < size;) {if (list[j] == list[i]) {for (k = j; k < size - 1; k++) {list[k] = list[k + 1];}size--;} else {j++;}}}
}int main() {int i = 0; int list1[] = {1, 2, 3, 5, 7};int list2[] = {3, 4, 5, 6, 8};int n1 = sizeof(list1) / sizeof(list1[0]);int n2 = sizeof(list2) / sizeof(list2[0]);int list3[MAX_SIZE];mergeAndRemoveDuplicates(list1, list2, n1, n2, list3);removeDuplicates(list3, n1 + n2);printf("Merged and duplicates removed list: ");for ( i = 0; i <8; i++) {printf("%d \n", list3[i]);}printf("\n");return 0;
}

#include <stdio.h>
#include <stdlib.h>struct ListNode {int val;struct ListNode* next;
};struct ListNode* createNode(int val) {struct ListNode* newNode = (struct ListNode*)malloc(sizeof(struct ListNode));newNode->val = val;newNode->next = NULL;return newNode;
}struct ListNode* mergeAndRemoveDuplicates(struct ListNode* list1, struct ListNode* list2) {struct ListNode* p = list1;struct ListNode* q = list2;struct ListNode* list3 = NULL; // 指向结果链表的头节点struct ListNode* tail = NULL; // 指向结果链表的尾节点while (p && q) {if (p->val < q->val) {// 若当前元素小于另一个表的当前元素，则将当前元素插入到结果链表中if (list3 == NULL) {list3 = tail = createNode(p->val);} else {tail->next = createNode(p->val);tail = tail->next;}p = p->next;} else if (p->val > q->val) {// 若当前元素大于另一个表的当前元素，则将当前元素插入到结果链表中if (list3 == NULL) {list3 = tail = createNode(q->val);} else {tail->next = createNode(q->val);tail = tail->next;}q = q->next;} else {  // 相同元素，只保留一个if (list3 == NULL) {list3 = tail = createNode(p->val);} else {tail->next = createNode(p->val);tail = tail->next;}p = p->next;q = q->next;}}// 将剩余的元素插入结果链表中while (p) {tail->next = createNode(p->val);tail = tail->next;p = p->next;}while (q) {tail->next = createNode(q->val);tail = tail->next;q = q->next;}// 删除结果链表中重复的元素struct ListNode* cur = list3;while (cur && cur->next) {if (cur->val == cur->next->val) {struct ListNode* temp = cur->next;cur->next = cur->next->next;free(temp);} else {cur = cur->next;}}return list3;
}void printList(struct ListNode* head) {struct ListNode* cur = head;while (cur != NULL) {printf("%d ", cur->val);cur = cur->next;}printf("\n");
}int main() {struct ListNode* list1 = createNode(1);list1->next = createNode(2);list1->next->next = createNode(3);list1->next->next->next = createNode(5);list1->next->next->next->next = createNode(7);struct ListNode* list2 = createNode(3);list2->next = createNode(4);list2->next->next = createNode(5);list2->next->next->next = createNode(6);list2->next->next->next->next = createNode(8);struct ListNode* list3 = mergeAndRemoveDuplicates(list1, list2);printf("Merged and duplicates removed list: ");printList(list3);// 释放链表的内存空间struct ListNode* temp;while (list3) {temp = list3;list3 = list3->next;free(temp);}return 0;
}

2-8设双链表中的结点包括4个部分：前驱指针llink，后继指针rlink，数据域data，访问频度freq，初始时将各结点的freq设置为0。当对某结点访问时使该结点的freq增加1，并且将链表按照访问freq递减的顺序进行排序。请编写算法实现以上功能

#include <stdio.h>
#include <stdlib.h>struct DoubleListNode {int data;int freq;struct DoubleListNode* llink;struct DoubleListNode* rlink;
};struct DoubleListNode* createNode(int data) {struct DoubleListNode* newNode = (struct DoubleListNode*)malloc(sizeof(struct DoubleListNode));if (newNode == NULL) {printf("Memory allocation failed.\n");exit(1);}newNode->data = data;newNode->freq = 0;newNode->llink = NULL;newNode->rlink = NULL;return newNode;
}void insertNode(struct DoubleListNode** head, int data) {struct DoubleListNode* newNode = createNode(data);if (*head == NULL) {*head = newNode;return;}// 插入到链表头部newNode->rlink = *head;(*head)->llink = newNode;*head = newNode;
}void increaseFreq(struct DoubleListNode** head, int data) {if (*head == NULL) {return;}struct DoubleListNode* cur = *head;while (cur != NULL) {if (cur->data == data) {cur->freq++;// 调整链表顺序struct DoubleListNode* prev = cur->llink;while (prev != NULL && prev->freq < cur->freq) {struct DoubleListNode* next = cur->rlink;if (prev->llink) {prev->llink->rlink = cur;}cur->llink = prev->llink;cur->rlink = prev;prev->llink = cur;if (next) {next->llink = prev;}prev->rlink = next;prev = cur->llink;}break;}cur = cur->rlink;}
}void printList(struct DoubleListNode* head) {struct DoubleListNode* cur = head;while (cur != NULL) {printf("(%d,%d) ", cur->data, cur->freq);cur = cur->rlink;}printf("\n");
}void freeList(struct DoubleListNode* head) {struct DoubleListNode* cur = head;while (cur != NULL) {struct DoubleListNode* temp = cur;cur = cur->rlink;free(temp);}
}int main() {struct DoubleListNode* head = NULL;insertNode(&head, 3);insertNode(&head, 5);insertNode(&head, 2);insertNode(&head, 8);printf("Original list: ");printList(head);increaseFreq(&head, 2);increaseFreq(&head, 5);increaseFreq(&head, 3);printf("Updated list: ");printList(head);// 释放链表的内存空间freeList(head);return 0;
}