reverse k group 

 1     ListNode *reverseKGroup(ListNode *head, int k) {
 2         // Start typing your C/C++ solution below
 3         // DO NOT write int main() function
 4         if( k<= 1 || head == NULL) return head;
 5         
 6         ListNode * root = new ListNode( -1 );
 7         root->next = head;
 8         ListNode* ptr1 = root;
 9         ListNode* ptr2 ;
10         ListNode* tmp, *tmp2,*tmp3;
11         
12         int count = 1;
13         while( head != NULL )
14         {
15             if( count < k ) {
16                 head = head -> next ;
17                 count ++;
18                 continue;          
19             }
20             tmp = head->next;
21             
22             head = ptr1 -> next;
23             ptr2 = head->next;
24             for( int i=1;i<k;i++)
25             {
26                 head -> next = ptr2-> next;
27                 ptr2->next = ptr1 -> next;
28                 ptr1 -> next = ptr2;
29                                
30                 ptr2 = head->next;
31                             
32             } 
33             ptr1 = head;
34             head = tmp;
35             count = 1;
36         }
37         return root->next;
38     }

 

posted on 2013-07-03 19:25  jumping_grass  阅读(209)  评论(0)    收藏  举报

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