Leetcode ☞ 86. Partition List ☆

86. Partition List

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Question

Total Accepted: 60658  Total Submissions: 208869  Difficulty: Medium

Given a linked list and a value x, partition it such that all nodes less than x come before nodes greater than or equal to x.

You should preserve the original relative order of the nodes in each of the two partitions.

For example,
Given 1->4->3->2->5->2 and x = 3,
return 1->2->2->4->3->5.

我的AC（0ms，最快一批）：

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     struct ListNode *next;
 * };
 */
struct ListNode* partition(struct ListNode* head, int x) {
    if(!head || !head->next) return head;
    
    struct ListNode *small, *big, *smallHead, *bigHead;
    small = smallHead = (struct ListNode*)malloc(sizeof(struct ListNode));//为表头指针开辟空间,即起始点。
    big = bigHead = (struct ListNode*)malloc(sizeof(struct ListNode));
    
    while(head){
        if(head->val < x)
            small = small->next = head;
        else
            big = big->next = head;
            
        head = head->next;
    }
    big->next = NULL;
    small->next = bigHead->next;
    return smallHead->next;
}