题目：

题解：

class Solution {
public:ListNode* partition(ListNode* head, int x) {ListNode* small = new ListNode(0);ListNode* smallHead = small;ListNode* large = new ListNode(0);ListNode* largeHead = large;while (head != nullptr) {if (head->val < x) {small->next = head;small = small->next;} else {large->next = head;large = large->next;}head = head->next;}large->next = nullptr;small->next = largeHead->next;return smallHead->next;}
};