insertion-sort-list.cpp

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */
class Solution {
public:
    ListNode* insertionSortList(ListNode* head) {
        ListNode* start = new ListNode(0);
        start->next = head;
        ListNode* cur = head, * prev = start;
        while(cur){
            if(cur->next and cur->next->val < cur->val){
                while(prev->next and prev->next->val < cur->next->val)
                    prev = prev->next;
                ListNode* temp = prev->next;
                prev->next = cur->next;
                cur->next = cur->next->next;
                prev->next->next = temp;
                prev = start;
            }
            else
                cur = cur->next;
        }
        return start->next;
    }
};