LeetCode OJ--Partition List

http://oj.leetcode.com/problems/partition-list/

链表的处理

#include <iostream>
using namespace std;

struct ListNode {
     int val;
     ListNode *next;
     ListNode(int x) : val(x), next(NULL) {}
 };

class Solution {
public:
    ListNode *partition(ListNode *head, int x) {
        ListNode *head1 = NULL,*head2 = NULL,*tail1 = NULL,*tail2 = NULL,*p = NULL;
        p = head;
        bool flag1 = ,flag2 = ;
        while(p)
        {
            if(p->val<x)
            {
                if(flag1 == )
                {
                    head1 = tail1 = p;
                    flag1 = ;
                }
                else
                {
                    tail1->next = p;
                    tail1 = p;
                }
            }
            else
            {
                if(flag2 == )
                {
                    head2 = tail2 = p;
                    flag2 = ;
                }
                else
                {
                    tail2->next = p;
                    tail2 = p;
                }
            }
            p = p->next;
        }
        if(head1 == tail1 && tail1 == NULL)
            return head2;
        tail1->next = head2;
        if(tail2)
        tail2->next = NULL;
        return head1;

    }
};

int main()
{
    ListNode *n1 = new ListNode();
    ListNode *n2 = new ListNode();
    ListNode *n3 = new ListNode();
    ListNode *n4 = new ListNode();
    ListNode *n5 = new ListNode();
    ListNode *n6 = new ListNode();
    n1->next = n2;
    n2->next = n3;
    n3->next = n4;
    n4->next = n5;
    n5->next = n6;
    ListNode *ans;
    Solution myS;
    ans = myS.partition(NULL,);
    return ;
}