习题11-7 奇数值结点链表

bonfirelit

于 2021-05-17 17:59:43 发布

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本文链接：https://blog.youkuaiyun.com/bonfirelit/article/details/116942200

该博客探讨了如何重组链表，使得原链表中奇数位置的节点形成一个新的链表。通过分析和代码实现，展示了如何寻找并连接奇数或偶数节点来完成这一操作。

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https://pintia.cn/problem-sets/12/problems/365

代码：

思路

原链表第一个元素为奇（偶）数，则找到第一个偶（奇）数，将偶（奇）数新建节点连成新的链表。

struct ListNode *readlist()
{
    struct ListNode* head = NULL;
    struct ListNode* last = NULL;
    int num;
    while(1) {
        scanf("%d", &num);
        if(num == -1) break;
        struct ListNode* p = (struct ListNode*)malloc(sizeof(struct ListNode));
        p->data = num;
        p->next = NULL;
        if(head == NULL) {
            head = p;
            last = head;
        }
        else {
            last->next = p;
            last = p;
        }
    }
    return head;
}
struct ListNode *getodd( struct ListNode **L )
{
    if(!*L) return NULL;
    struct ListNode* Head = *L;
    struct ListNode *oddhead, *oddlast, *evenhead, *evenlast, *t;
    oddhead = oddlast = evenhead = evenlast = Head;
    t = Head;
    if(Head->data % 2 == 1)//链表第一个是奇数
    {
        evenhead = NULL;
        //找到第一个偶数
        while(t && t->data % 2 == 1) {
            oddlast = t;//oddlast指向t前一个
            t = t->next;
        }
        while(t) {
            //t所指为偶数
            if(t->data % 2 == 0) {//则申请空间存放
                struct ListNode* p = (struct ListNode*)malloc(sizeof(struct ListNode));
                p->data = t->data;
                p->next = NULL;
                if(evenhead == NULL) {
                    evenhead = p;
                    evenlast = p;
                }
                else {
                    evenlast->next = p;
                    evenlast = p;
                }
                //删除原链表该元素
                if(t->next) {
                    if(t->next->data % 2 == 1) {
                        oddlast->next = t->next;
                        oddlast = t->next;
                    }
                }
                else {
                    oddlast->next = NULL;
                }
            }
            t = t->next;
        }
        *L = evenhead;
        return oddhead;
    }
    else {
         oddhead = NULL;
        //找到第一个奇数
        while(t && t->data % 2 == 0) {
            evenlast = t;//evenlast指向t前一个
            t = t->next;
        }
        while(t) {
            //t所指为奇数
            if(t->data % 2 == 1) {//则申请空间存放
                struct ListNode* p = (struct ListNode*)malloc(sizeof(struct ListNode));
                p->data = t->data;
                p->next = NULL;
                if(oddhead == NULL) {
                    oddhead = p;
                    oddlast = p;
                }
                else {
                    oddlast->next = p;
                    oddlast = p;
                }
                //删除原链表该元素
                if(t->next) {
                    if(t->next->data % 2 == 0) {
                        evenlast->next = t->next;
                        evenlast = t->next;
                    }
                }
                else {
                    evenlast->next = NULL;
                }
            }
            t = t->next;
        }
        *L = evenhead;
        return oddhead;
    }
}