如何用 Java 创建带列表的树集？
TreeSet 是 Java 中 SortedSet 接口的一个实现，使用树进行存储。通过将列表传递给 Java 中的 TreeSet 构造函数，可以从列表创建 TreeSet，或者我们可以遍历完整的列表，并将列表的每个元素添加到 TreeSet 中。
例:
Input : List = [a, b, c]
Output: TreeSet = [a, b, c]
Input : List = [1, 2, 3]
Output: TreeSet = [1, 2, 3]
方法 1:
- Create a list object.
- Enter multiple inputs in the list.
- Create a treeset object.
- Initialize an object with a constructor and pass a List object in it.
- Print tree set.
下面是上述方法的实现:
Java 语言(一种计算机语言，尤用于创建网站)
// Java Program to Create a TreeSet with a List
import java.util.ArrayList;
import java.util.List;
import java.util.TreeSet;
public class ExampleTreeSet {
public static void main(String a[])
{
// Create new List
List<String> fruitlist = new ArrayList<String>();
fruitlist.add("Mango");
fruitlist.add("Apple");
fruitlist.add("Grape");
fruitlist.add("Papaya");
// Printing ArrayList
System.out.println("Fruit List : " + fruitlist);
// Create a TreeSet with the list
TreeSet<String> tree_set
= new TreeSet<String>(fruitlist);
// Print TreeSet
System.out.println("TreeSet from List : "
+ tree_set);
}
}
Output
Fruit List : [Mango, Apple, Grape, Papaya]
TreeSet from List : [Apple, Grape, Mango, Papaya]
时间复杂度: O(N)
方法 2:
- Create a list object.
- Enter multiple inputs in the list.
- Create a treeset object.
- Start the list traversal and add the element to the tree set.
- After traversing, print the tree set.
下面是上述方法的实现:
T3】JavaT5
// Java Program to Create a TreeSet with a List
import java.util.ArrayList;
import java.util.List;
import java.util.TreeSet;
public class ExampleTreeSet {
public static void main(String a[])
{
// Create new List
List<String> fruitlist = new ArrayList<String>();
fruitlist.add("Mango");
fruitlist.add("Apple");
fruitlist.add("Grape");
fruitlist.add("Papaya");
// Printing ArrayList
System.out.println("Fruit List : " + fruitlist);
// Create a TreeSet
TreeSet<String> tree_set = new TreeSet<String>();
// Add each element in the TreeSet
for (String i : fruitlist)
tree_set.add(i);
// Print TreeSet
System.out.println("TreeSet from List : "
+ tree_set);
}
}
T6T8输出T1
时间复杂度: O(N)
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