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  • Java list

    1.add remove sort

    import java.util.ArrayList;
    import java.util.Collections;
    import java.util.Comparator;
    
    public class listTest{
    	public static void main(String []args){
    		ArrayList<String> list = new ArrayList<String>();
    		
    		// Add method
    		
    		list.add("one");
    		list.add("two");
    		list.add("three");
    		System.out.println(list);
    		
    		// Sort method
    		
    		Collections.sort(list);    // default Sort
    		System.out.println(list);  
    		
    		Collections.sort(list,new listSort());
    		System.out.println(list);
    		
    		// Delete method
    		
    		list.remove("two");
    		System.out.println(list);
    		
    		list.remove(0);
    		System.out.println(list);
    		
    	}
    }
    class listSort implements Comparator<String>{
    	public int compare(String a, String b){
    		return b.compareTo(a);
    	}
    }
    

    2.Difference between ArrayList and LinkedList

    Add an items to fist location 100000 times .

    import java.util.ArrayList;
    import java.util.LinkedList;
    
    public class diffLists {
    	public static void main(String[] args) {
    
    		// Array List
    
    		long start = System.currentTimeMillis();
    		ArrayList<String> arraylist = new ArrayList<String>();
    		for (int i = 0; i < 100000; i++) {
    			arraylist.add(0, "hello");
    		}
    		long end = System.currentTimeMillis();
    		System.out.println("ArrayList Time use: " + (end - start) +"ms");
    
    		// Linked List
    
    		start = System.currentTimeMillis();
    		LinkedList<String> linkedlist = new LinkedList<String>();
    		for (int i = 0; i < 100000; i++) {
    			linkedlist.add(0, "hello");
    		}
    		end = System.currentTimeMillis();
    		System.out.println("LinkedList Time use: " + (end - start)+"ms");
    	}
    }
    
    ArrayList Time use: 972ms
    LinkedList Time use: 5ms
    
    
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  • 原文地址:https://www.cnblogs.com/cyno/p/4451766.html
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