資料結構:單向連結串列系列3--刪除節點
阿新 • • 發佈:2019-08-31
刪除節點(3步操作)
刪除步驟
1) 找到待刪除節點的前驅
2) 修改前驅節點的指標域指向待刪除節點的後繼節點
3)釋放待刪除的節點的記憶體空間
//todo:沒有c#的程式碼新增上去。修改結構,新增一個尾部節點地址的指標
c語言實現:
因為連結串列中的每個節點都是使用malloc()動態建立的,所以需要呼叫free()釋放待刪除節點佔用的記憶體空間。
// A complete working C program to demonstrate deletion in singly // linked list #include <stdio.h> #include <stdlib.h> // A linked list node struct Node { int data; struct Node *next; }; /* Given a reference (pointer to pointer) to the head of a list and an int, inserts a new node on the front of the list. */ void push(struct Node** head_ref, int new_data) { struct Node* new_node = (struct Node*) malloc(sizeof(struct Node)); new_node->data = new_data; new_node->next = (*head_ref); (*head_ref) = new_node; } /* Given a reference (pointer to pointer) to the head of a list and a key, deletes the first occurrence of key in linked list */ void deleteNode(struct Node **head_ref, int key) { // Store head node struct Node* temp = *head_ref, *prev; // If head node itself holds the key to be deleted if (temp != NULL && temp->data == key) { *head_ref = temp->next; // Changed head free(temp); // free old head return; } // Search for the key to be deleted, keep track of the // previous node as we need to change 'prev->next' while (temp != NULL && temp->data != key) { prev = temp; temp = temp->next; } // If key was not present in linked list if (temp == NULL) return; // Unlink the node from linked list prev->next = temp->next; free(temp); // Free memory } // This function prints contents of linked list starting from // the given node void printList(struct Node *node) { while (node != NULL) { printf(" %d ", node->data); node = node->next; } } /* Drier program to test above functions*/ int main() { /* Start with the empty list */ struct Node* head = NULL; push(&head, 7); push(&head, 1); push(&head, 3); push(&head, 2); puts("Created Linked List: "); printList(head); deleteNode(&head, 1); puts("\nLinked List after Deletion of 1: "); printList(head); return 0; }
因為涉及到遍歷,時間複雜度O(n)
輸出
Created Linked List: 2 3 1 7 Linked List after Deletion of 1: 2 3 7
java:
// A complete working Java program to demonstrate deletion in singly // linked list class LinkedList { Node head; // head of list /* Linked list Node*/ class Node { int data; Node next; Node(int d) { data = d; next = null; } } /* Given a key, deletes the first occurrence of key in linked list */ void deleteNode(int key) { // Store head node Node temp = head, prev = null; // If head node itself holds the key to be deleted if (temp != null && temp.data == key) { head = temp.next; // Changed head return; } // Search for the key to be deleted, keep track of the // previous node as we need to change temp.next while (temp != null && temp.data != key) { prev = temp; temp = temp.next; } // If key was not present in linked list if (temp == null) return; // Unlink the node from linked list prev.next = temp.next; } /* Inserts a new Node at front of the list. */ public void push(int new_data) { Node new_node = new Node(new_data); new_node.next = head; head = new_node; } /* This function prints contents of linked list starting from the given node */ public void printList() { Node tnode = head; while (tnode != null) { System.out.print(tnode.data+" "); tnode = tnode.next; } } /* Drier program to test above functions. Ideally this function should be in a separate user class. It is kept here to keep code compact */ public static void main(String[] args) { LinkedList llist = new LinkedList(); llist.push(7); llist.push(1); llist.push(3); llist.push(2); System.out.println("\nCreated Linked list is:"); llist.printList(); llist.deleteNode(1); // Delete node at position 4 System.out.println("\nLinked List after Deletion at position 4:"); llist.printList(); } }
文章來源:https://www.geeksforgeeks.org/linked-list-set-3-deleting-n