题目：

题解：

struct ListNode* partition(struct ListNode* head, int x) {struct ListNode* small = malloc(sizeof(struct ListNode));struct ListNode* smallHead = small;struct ListNode* large = malloc(sizeof(struct ListNode));struct ListNode* largeHead = large;while (head != NULL) {if (head->val < x) {small->next = head;small = small->next;} else {large->next = head;large = large->next;}head = head->next;}large->next = NULL;small->next = largeHead->next;return smallHead->next;
}