Rotate List
Given the head of a linked list, rotate the list to the right by k places.
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Example 1:
Input: head = [1,2,3,4,5], k = 2
Output: [4,5,1,2,3]
Example 2:
Input: head = [0,1,2], k = 4
Output: [2,0,1]
Solution
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class Solution {
public:
ListNode* rotateRight(ListNode* head, int k) {
if (head == nullptr) {
return nullptr;
}
int i = 0;
ListNode* p = head;
ListNode* fixHead = head;
int size = 0;
ListNode* sizePtr = head;
while (sizePtr) {
size++;
sizePtr = sizePtr->next;
}
k = k % size;
while (i < k) {
while (p->next != nullptr && p->next->next != nullptr) {
p = p->next;
}
ListNode* prevNode = p;
ListNode* tailNode = p->next;
if (tailNode == nullptr) {
return fixHead;
}
p->next = nullptr;
tailNode->next = fixHead;
p = tailNode;
fixHead = p;
i++;
}
return fixHead;
}
};
