OJ 1131번 해답

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#include <stdio.h> #include <stdlib.h> struct node { int data; struct node *prev; struct node *next; }; struct node *head = 0; // returns the pointer to the node which has _data // returns null if no node has _data struct node* whereIsNode(int _data) { struct node *temp = head; while (temp != 0) { if (temp->data == _data) { break; } temp = temp->next; } return temp; } void addToDLL(int n) { struct node *cur; cur = (struct node *)malloc(sizeof(struct node)); cur->next = cur->prev = 0; cur->data = n; // check if there is no node if (head == 0) { head = cur; return; } // find the last node { struct node *temp = head; while (temp->next != 0) { temp = temp->next; } temp->next = cur; cur->prev = temp; return; } } void showDLL() { struct node *cur = head; while (cur != 0) { printf("%d ", cur->data); cur = cur->next; } } void showNeighbors(int _data) { struct node *temp; temp = whereIsNode(_data); if (temp == 0) { printf("-999\n"); return; } else { // prev prev if (temp->prev != 0) { if (temp->prev->prev != 0) { printf("%d ", temp->prev->prev->data); } else { printf("-999 "); } } else { printf("-999 "); } // next next if (temp->next != 0) { if (temp->next->next != 0) { printf("%d \n", temp->next->next->data); } else { printf("-999 \n"); } } else { printf("-999 \n"); } } } int main(void) { addToDLL(1); addToDLL(2); addToDLL(3); addToDLL(4); addToDLL(5); addToDLL(6); addToDLL(7); addToDLL(8); showNeighbors(5); // 3, 7 showNeighbors(8); // 6, -999 showNeighbors(1); // -999, 3 showNeighbors(100); // -999 return 0; }