Java实现寻找列表List中最后一个元素
如何在一个元素列表List中找到最后一个元素？
import java.util.LinkedList;
import java.util.List;
import java.util.NoSuchElementException;
/**
* (*) Find the last element of a list.
* <p>
* Check P01Test class for test cases related to this problem.
*/
public class P01 {
/*
You could solve this using many different approaches.
If you work with List interface then you can find the last element using List size as shown below.
*/
public static <T> T last(List<T> elements) {
int numberOfElements = elements.size();
return elements.get(numberOfElements - 1);
}
/*
Another way to solve this is by using LinkedList instead of a List.
LinkedList provides a builtin getLast method.
*/
public static <T> T last(LinkedList<T> elements) {
return elements.getLast();
}
/*
A functional approach could be to use recursion. We call the function recusively with a sub list which ignores the 0th element.
When we reach the end i.e. size of the list is 1 then we return that element.
*/
public static <T> T lastRecursive(List<T> elements) {
if (elements == null || elements.isEmpty()) {
throw new NoSuchElementException();
}
if (elements.size() == 1) {
return elements.get(0);
}
return lastRecursive(elements.subList(1, elements.size()));
}
}