Leetcode: Sort List - 插入

Sort a linked list using insertion sort.

还是插入排序简单呀。

/** * 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 == NULL || head->next == NULL) {            return head;        }        ListNode *cur = head->next;        head->next = NULL;        ListNode *prev = NULL;        ListNode *target = NULL;        ListNode *tmp = NULL;        while (cur != NULL) {            prev = NULL;            target = head;            while (target != NULL && target->val <= cur->val) {                prev = target;                target = target->next;            }            if (prev == NULL) {                head = cur;            }            else {                prev->next = cur;            }            tmp = cur->next;            cur->next = target;            cur = tmp;        }                return head;    }};

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/** * 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 == NULL || head->next == NULL) {            return head;        }                ListNode *insertion = NULL;        ListNode *prev = NULL;        ListNode *tmp = NULL;        ListNode *cur = head->next;        head->next = NULL;        while (cur != NULL) {            insertion = head;            while (insertion != NULL && insertion->val < cur->val) {                prev = insertion;                insertion = insertion->next;            }                        tmp = cur->next;            if (insertion == head) {                cur->next = head;                head = cur;            }            else {                 prev->next = cur;                cur->next = insertion;            }            cur = tmp;        }                return head;    }};