🐹双指针
前面添加一个哑节点，可以避免头节点的特殊处理。
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| class Solution {
public:
ListNode* removeNthFromEnd(ListNode* head, int n) {
ListNode* nou = new ListNode(0);
nou->next = head;
auto slow = nou;
auto quick = nou;
++n;
while(n--)
quick = quick->next;
while(quick) {
slow = slow->next;
quick = quick->next;
}
auto nx = slow->next->next;
slow->next = nx;
return nou->next;
}
};
|
Accepted
208/208 cases passed (4 ms)
Your runtime beats 92.07 % of cpp submissions
Your memory usage beats 11.12 % of cpp submissions (8.6 MB)
🐶格外空间
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| class Solution {
public:
ListNode* removeNthFromEnd(ListNode* head, int n) {
vector<ListNode*> nodes;
auto h = head;
while(h) {
nodes.push_back(h);
h = h->next;
}
int pos = nodes.size() - n;
if(pos - 1 < 0)
return head->next;
nodes[pos - 1]->next = pos + 1 >= nodes.size() ? nullptr : nodes[pos + 1];
return head;
}
};
|
Accepted
208/208 cases passed (4 ms)
Your runtime beats 92.07 % of cpp submissions
Your memory usage beats 5.22 % of cpp submissions (8.8 MB)
