#include #include struct ListNode { int val; struct ListNode *next; }; struct ListNode *partition(struct ListNode *head, int x) { struct ListNode dummy; struct ListNode *prev1 = &dummy, *pivot; dummy.next = head; for (pivot = head; pivot != NULL; pivot = pivot->next) { if (pivot->val >= x) { break; } prev1 = pivot; } struct ListNode *p = pivot->next; struct ListNode *prev2 = pivot; while (p != NULL) { if (p->val < x) { prev2->next = p->next; p->next = prev1->next; prev1->next = p; prev1 = p; p = prev2->next; } else { prev2 = p; p = p->next; } } return dummy.next; } int main(int argc, char **argv) { if (argc < 2) { fprintf(stderr, "Usage: ./test target n1 n2 n3...\n"); exit(-1); } int i, target = atoi(argv[1]); struct ListNode *head = NULL; struct ListNode *prev = NULL; struct ListNode *p; for (i = 0; i < argc - 2; i++) { p = malloc(sizeof(*p)); p->val = atoi(argv[i + 2]); p->next = NULL; if (head == NULL) { head = p; prev = head; } else { prev->next = p; prev = p; } } p = partition(head, target); while (p != NULL) { printf("%d ", p->val); p = p->next; } printf("\n"); return 0; }