LeetCode:Insertion Sort List

Insertion Sort List

Total Accepted: 62373  Total Submissions: 220367  Difficulty: Medium

Sort a linked list using insertion sort.

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  Linked List Sort

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  (M) Sort List

思路：

1.将链表分成两个部分（已排序和未排序）；

2.搜索排序部分插入点；

3.插入

code:

/**
 * 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) {
        
        ListNode *dummy = new ListNode(-1);
        ListNode *cur = head;
        ListNode *tmp = dummy;
        while(cur) {
            ListNode *next = cur->next;
            while(tmp->next && tmp->next->val < cur->val) tmp = tmp->next;
            cur->next = tmp->next;
            tmp->next = cur;
            tmp = dummy;
            cur = next;
        }
        return dummy->next;
    }
};