[数据结构与算法]#143 重排链表

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     struct ListNode *next;
 * };
 */
void reorderList(struct ListNode* head){
    struct ListNode **result = (struct ListNode **)malloc(sizeof(struct ListNode *) * 50000);
    memset(result, 0, sizeof(struct ListNode *) * 50000);
    int i = 0, j=0;
    while(head)
    {
        result[i++] = head;
        head = head->next;
    }
    head = result[0];
    for(j=i-1,i=1; i<j; j--,i++)
    {
        head->next = result[j];
        head = head->next;
        head->next = result[i];
        head = head->next;
    }
    if(i==j) 
    {
        head->next = result[i];
        head = head->next;
    }
    head->next = NULL;
    head = result[0];
    free(result);
}