Commit ad2a9951 authored by zhayao's avatar zhayao
Browse files

keep going

parent 92e9d7ee
......@@ -243,8 +243,48 @@ public:
}
};
// Reverse Nodes in k-Group
// Example:
// Given this linked list: 1->2->3->4->5
// For k = 2, you should return: 2->1->4->3->5
// For k = 3, you should return: 3->2->1->4->5
// Given a linked list, reverse the nodes of a linked list k at a time and return its modified list.
// k is a positive integer and is less than or equal to the length of the linked list. If the number of nodes is not a multiple of k then left-out nodes in the end should remain as it is.
// Note:
// Only constant extra memory is allowed.
// You may not alter the values in the list's nodes, only nodes itself may be changed.
/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
ListNode* reverseKGroup(ListNode* head, int k) {
ListNode* current = head;
ListNode* next = nullptr;
ListNode* prev = nullptr;
while(current && k){
k--;
next = current->next;
current->next = prev;
prev = current;
current = next;
}
head->next = next;
return prev;
}
};
......
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