Interpretation of Java documentation: Analysis of the function of the lastIndexOf() method of the LinkedList class

Java Document Interpretation: Function analysis of the lastIndexOf() method of the LinkedList class requires specific code examples

The LinkedList class is one of the commonly used linked list data structure classes in Java. It provides a series of methods for operating and managing linked lists. Among them, the lastIndexOf() method is a common method in the LinkedList class. This article will analyze the function of this method and provide specific code examples.

The function of the lastIndexOf() method of the LinkedList class is to return the index of the last occurrence of the specified element in the linked list. If the linked list does not contain the element, -1 is returned. The declaration of this method is as follows:

public int lastIndexOf(Object o)

In the parameter part of the method, we need to pass in an object o, which is the element we want to find.

Below, we use a specific code example to further understand the use of the lastIndexOf() method.

import java.util.LinkedList;

public class LinkedListExample {
    public static void main(String[] args) {
        LinkedList<String> linkedList = new LinkedList<>();

        // 向链表中添加一些元素
        linkedList.add("apple");
        linkedList.add("banana");
        linkedList.add("orange");
        linkedList.add("apple");
        linkedList.add("watermelon");

        // 查找元素"apple"在链表中最后一次出现的位置
        int lastIndex = linkedList.lastIndexOf("apple");
        
        // 输出结果
        if (lastIndex != -1) {
            System.out.println("元素'apple'最后一次出现的位置为：" + lastIndex);
        } else {
            System.out.println("元素'apple'未在链表中出现。");
        }
    }
}

In the above code, we first create a LinkedList object linkedList and add some elements to it. Then, we use the lastIndexOf() method to find the last occurrence of the element "apple" in the linked list. Finally, based on the return value, we output the corresponding result.

Running the above code, we can get the following output:

元素'apple'最后一次出现的位置为：3

It can be seen that the lastIndexOf() method successfully located the position where the element "apple" last appeared in the linked list, that is Index 3.

It should be noted that the lastIndexOf() method searches forward from the end of the linked list. Therefore, its time complexity is O(n), where n is the length of the linked list.

To summarize, the lastIndexOf() method of the LinkedList class is used to find the index of the last occurrence of a specified element in the linked list. Through the code examples provided in this article, we can better understand and apply this method.

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