在 Java 中使用树集合上的排序逻辑从集合中获取最小值元素
原文:https://www . geeksforgeeks . org/通过使用 java 中的树集合上的排序逻辑从集合中获取最小值元素/
为了获得用户定义对象的值元素，需要在 TreeSet 中实现排序逻辑。现在，为了在用户定义的对象上实现排序逻辑，需要通过 TreeSet 构造函数调用传递 Comparator 对象。此外，比较器实现将保存排序逻辑。为此，需要覆盖 【比较()】 方法，以便在用户定义的对象上提供排序逻辑。最后，使用 优先() 方法提取出最少的元素。
插图:
Input : Set: ["A"=36678 , "B"=456456 ,"C"=76434 ,"D"=4564]
Output: Least value => element: D, value: 4564
Input : Set: ["x"=1, "y"=2 ,"z"=3]
Output: Set: Least value =>element: x, value: 1
接近
获取最小值元素 TreeSet
- 使用比较器对用户定义类的对象进行排序。
- 实现覆盖 compare()方法的排序功能，以便按值对 TreeSet 进行排序。
- 排序后，TreeSet 的第一个对象将是值最小的元素。
实施:
示例
Java
// Java program to find out the least value element
// in a TreeSet
// Importing java input output libraries
// Importing Comparator and TreeSet class
// from java.util package
import java.io.*;
import java.util.Comparator;
import java.util.TreeSet;
// Two auxiliary classes are required
// Class1- Sorting logic class invoking comparator
// Class2- Element class
// Class3 - Main class(Implementation class)
// Class1- Sorting logic where
// comparator holds the sorting logic
class MySort implements Comparator<Element> {
@Override
// Overriding
// To provide the sorting logic to below created TreeSet
// in main() method using compare() method
public int compare(Element e1, Element e2)
{
// Condition check
// Comparing values of element
if (e1.getvalue() > e2.getvalue()) {
// If condition holds true
return 1;
}
else {
// If condition is false
return -1;
}
}
}
// Class- 2
// key for TreeSet --> Name
class Element {
// Member variables of this class
private String name;
private int value;
// Constructor of this class
public Element(String n, int s)
{
// Referring to same object
// using this keyword
this.name = n;
this.value = s;
}
// key--> Name
// Using name as a key for TreeSet
public String getname() { return name; }
// Return value for the given key(name)
public int getvalue() { return value; }
// Format in which output is returned
public String toString()
{
return "element: " + this.name
+ ", value: " + this.value;
}
}
// Main Class- Implementing sorting functionality
class GFG {
// Main driver method
public static void main(String[] args)
{
// Implementing sorting functionality with TreeSet
// by implementing Comparator and
// calling (MySort) from TreeSet constructor
// Creating an object of Treeset
// where object type is Element
TreeSet<Element> Tree
= new TreeSet<Element>(new MySort());
// Adding elements to adobe object of TreeSet
// Custom inputs
Tree.add(new Element("A", 36778));
Tree.add(new Element("B", 456456));
Tree.add(new Element("C", 76433));
Tree.add(new Element("D", 4564));
// Printing first element of above created TreeSet
// which will be least value among all elements
System.out.println("Least value =>" + Tree.first());
}
}
输出
Least value =>element: D, value: 4564
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