code/linked_list/linked_list.c

#include <stdio.h>
#include <stdlib.h>
struct  Node
{
   int data;
   struct Node* next;
};
struct Node* head;

// 在链表头节点插入一个值为x的节点
void Insert(int x){
   struct Node* temp = (struct Node*)malloc(sizeof(struct Node));
   temp->data = x;
   temp->next = head;
   // if(head != NULL)temp->next = head;
   head = temp;
}

// 迭代法实现反转列表
struct Node* Reverse1(struct Node* head){
   struct Node *Current,*Prev,*next;
   Current = head;
   Prev = NULL;
   while(Current != NULL){
      next = Current->next;
      Current->next = Prev;
      Prev = Current;
      Current = next;
   }
   head = Prev;
   return head;
}

// 递归法实现反转列表
void Reverse2(struct Node* p){
   if(p->next ==NULL){
      head = p;
      return;
   }
   Reverse2(p->next);
   struct Node* q = p->next;
   q->next = p;
   p->next = NULL;
}

// 链表内指定区间反转  调试好了
struct Node* reverseBetween(struct Node* head, int m, int n ) {
    // write code here
    if(head == NULL)return head;
    if(head->next == NULL)return head;
    if(m == n)return head;
    struct Node *Current,*Prev,*next,*start,*start_last;
    int i;
    Current = head;
    Prev = NULL;
    next = NULL;
    // 先找到开始位置
    for (i=1; i<m; i++) {
        next = Current->next;
        // Current->next = Prev;
        Prev = Current;
        Current = next;
    }
    // 标记
    start_last = Prev;
    start = Current;
    // 反转
    for (i=0; i<(n-m+1); i++) {
        next = Current->next;
        Current->next = Prev;
        Prev = Current;
        Current = next;
    }
    // 头尾节点重指向
    if(start != head){
        start->next = next;
        start_last->next = Prev;//start!=head的情况下，需要保留start上一个指针
    }
    else {
        start->next = next;
        head = Prev;//start==head的情况下，直接将head指向待反转的最后一个
    }
    return head;
}

//打印链表的所有值
void Print(){
   struct Node* temp = head;
   printf("List is:");
   while(temp){
      printf("%d",temp->data);
      temp = temp->next;
   }
   printf("\n");
}

void Print2(struct Node*p){
   if(p ==NULL){
      printf("\n");
      return;
   }
   // 正序打印
   // printf("%d",p->data);
   // Print2(p->next);

   // 反转打印
   printf("%d",p->data);
   Print2(p->next);
}

int main(){
   head = NULL;
   int n,x,i;
   printf("Please input the number of node:\n");
   scanf("%d",&n);
   for(i = 0;i<n;i++){
      printf("Please input the value of Node:\n");
      scanf("%d",&x);
      Insert(x);
      Print();
   }
   head = Reverse1(head);
   printf("Reverse linked list is:\n");
   Print();

   Reverse2(head);
   printf("Reverse linked list is:\n");
   Print();
   
   // head = reverseBetween(head,2,4);
   // Print();

   // printf("Print2 linked list is:\n");
   // Print2(head);

   // char name[100];
   // printf("What is your name?\n");
   // scanf("%s",name);
   // printf("Hello,%s,nice to meet you!\n",name);
}