题解 | 牛牛的链表交换

#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
void sort(int* array, int n) ;

typedef  struct list {
    int number;
    struct list* behind;
} list;


void InitList (list* ptr);
int main() {
    int n, i;

    scanf("%d", &n); /*输入数组长度*/
    getchar();

    if (n == 0) { /*判断数组长度是否合理*/
        return -1;
    }

    int array[100] = { 0 }; /*定义数组*/
    int* p = array; /*定义指针*/

    for (i = 0; i < n; i++) { /*输入n个正整数*/
        scanf("%d", array + i);
        getchar();
    }
    //sort(array,  n);
    list* head = NULL;
    list* link = NULL;
    int k;

    for (k = 0; k < n; k++) {
        list* alloc = (list*)malloc(sizeof(list));
        alloc->number = array[k];
        alloc->behind = NULL;

        if (head == NULL) {
            head = alloc;
            link = alloc;
        } else {
            link->behind = alloc;
            link = link->behind;
        }
    }
    //头部替换
    list* temp = head->behind;
    head->behind = temp->behind;
    temp->behind = head;
    head = temp;

    //尾部替换
    
    list* A = NULL;
    list* B = NULL;
    list* C = head;

    while (C->behind != NULL) {
        A = B;
        B = C;
        C = C->behind;
    }

    if (A!=NULL)
    {
        C->behind=B;
        A->behind=C;
        B->behind=NULL;
    }

    while (head != NULL) {
        printf("%d ", head->number);
        head = head->behind;
    }
    // for (i = 0; i < n; i++) {
    //     printf("%d ", array[i]);
    // }

    return 0;
}