Question

How to get array elements that appear more than once in Java

Answer 1

import java.util.*; 
import java.util.Map.Entry; 
 
public class MyClass {
    static Map<Integer, Integer> getMoreThanOnce(int arr[]) { 
        Map<Integer, Integer> map = new LinkedHashMap<Integer, Integer>(); 
             
        for (int i = 0; i < arr.length; i++) { 
            try { 
                map.put(arr[i], map.get(arr[i]) + 1); 
            } 
            catch (Exception e) { 
                map.put(arr[i], 1); 
            } 
        } 
        return map;
    }
    public static void main(String args[]) {
        int arr[] = {1, 6, 3, 1, 8, 9, 9, 1, 3, 4}; 
 
        Map<Integer, Integer> map = getMoreThanOnce(arr);
        
        for (Entry<Integer, Integer> mp : map.entrySet()) { 
            if (mp.getValue() > 1) { 
                System.out.print(mp.getKey() + " "); 
            } 
        } 
    }
}
 
 
 
/*
run:
 
1 3 9 
 
*/

 

70+ SQL courses for beginners and professionals