[leetcode] Insertion Sort List

使用插入排序算法对链表进行排序

最新推荐文章于 2021-11-16 15:52:48 发布

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本文介绍了一种使用插入排序算法对单链表进行排序的方法，并提供了详细的实现步骤和代码解释。

From : https://leetcode.com/problems/insertion-sort-list/

Sort a linked list using insertion sort.

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* insertionSortList(ListNode* head) {
        if(!head || !head->next) return head;
        ListNode *index, *cur=head->next, *p, *pre;
        ListNode *phead = new ListNode(0);
        phead->next = head;
        head->next = NULL;
        while(cur) {
            int val = cur->val;
            pre = phead;
            index = pre->next;
            p = cur->next;
            while(index && index->val<=val) {
                pre=index;
                index=index->next;
            }
            cur->next = index;
            pre->next = cur;
            cur = p;
        }
        head = phead->next;
        delete phead;
        return head;
    }
};